I will start with a confession that I wasn't particularly looking forward to this book. In fact, the Advanced Class Guide is the first book in the hardcover rulebook line that I seriously considered not getting. This is because its basic premise doesn't really offer me anything I want or need for my games. It's not that I'm opposed to new classes. Rather, the particular classes in this book don't fill any niches that I feel needed filling.
The Advanced Class Guide introduces ten new “hybrid” classes for the Pathfinder Roleplaying Game. As hybrid classes, they combine two existing classes together, offering a selection of abilities from both classes as well as new abilities that fit their combined flavour. These classes essentially provide a way of multiclassing without multiclassing. This is the fundamental reason why these classes mostly don't appeal to me. While they do have some new abilities, they don't offer any new flavour. In all cases, it's possible to create characters in the same style with the existing multiclass rules. Now, I should probably also confess that I like the multiclassing rules. Yes, there are problems with them (particularly with multiclass spellcasters), but as long as you can get away from the idea that “class” is synonymous with “profession”, you can create a huge variety of character types with them—and yes, they can even be effective characters. As there is already a way to combine the abilities of different classes, there really doesn't seem to be a place for hybrid classes. New classes should be exactly that—new. I have the same problem with the magus from Ultimate Magic, to be honest.
As well as multiclassing, the game also uses archetypes as a way of providing characters with a smattering of abilities from other classes. Archetypes provide ways to create characters that are just slight variants of existing classes, so that an entirely new class isn't necessary. The new classes in the Advanced Class Guide feel a lot like archetypes in many ways. In fact, in the original playtest document, they were alternate classes of both their parent classes. (Alternate classes are archetypes that change a large number of things about their parent class and so get a complete write-up while not being actual new classes.) However, this was changed in the final book, so they are now fully separate classes. I personally liked them better as alternate classes—though, honestly, even as alternate classes, these classes still felt mostly unnecessary.
Nevertheless, despite my misgivings, I did decide to get the book, feeling that there would likely be other parts of the book (like new feats and spells) that would be useful to me, and—who knows?—I might even decide that I like the new classes after all. Alas, it didn't quite work out that way. I'm not saying that the Advanced Class Guide is a bad book. It does what it set out to do, and it does it pretty well. It's just going to see very little use in my games. I might use the swashbuckler and shaman, though.
All that said, let's take a look at what it has to offer and examine both its strengths and its weaknesses.
The first chapter covers the ten new hybrid classes, presenting each in the standard format used throughout Pathfinder Roleplaying Game books. First up is the arcanist, which is a hybrid of sorcerer and wizard. The concept of this class is kind of intriguing but at the same time somewhat bewildering. Sorcerer and wizard are two classes that do not combine well using the standard multiclass rules. However, they're also two classes that I can't see many people wanting to multiclass between even if the combination worked well. Arcanists' main ability is that they use a system to cast spells that is a combination of both prepared and spontaneous. They learn spells like a wizard and can prepare a small number of them each day. However, their slots for casting them are separate from the slots for preparing them. They can cast their prepared spells any number of times and in any combination, up to the limit of their spells per day. It's an interesting system, but again, one that I don't really see as being necessary. There are strengths to prepared casters, and strengths to spontaneous casters. Arcanists sit somewhere in the middle and don't really seem to benefit from either side all that much. Arcanists also learn arcanist exploits as they go up in level. These abilities allow them to bend the rules of magic in various ways, such as counterspelling as an immediate action or using metamagic feats without increasing the casting time. All arcanists have an arcane reservoir, which powers their exploits. I like a lot of the exploits, but they aren't that different in concept to arcane discoveries for wizards (first introduced in Ultimate Magic). With only minor modifications, there's no reason these couldn't be turned into arcane discoveries.
Next up is the bloodrager, which combines the abilities of a barbarian and a sorcerer. Bloodragers have a bloodline like a sorcerer, and the ability to rage, which is called “bloodrage” here for reasons that aren't immediately apparent (other than the name of the class). At 4th level, which is when they first gain the ability to cast spells, they also gain the ability to cast spells while raging. They gain very little else that you wouldn't get by simply playing a barbarian/sorcerer. Bloodragers have very limited spellcasting (four levels of spells gained at a rate very similar, though not identical, to paladins and rangers), so barbarian/sorcerers would not need to take a lot of levels of sorcerer, decreasing the problems that come from multiclass spellcasters.
The next two classes are the brawler (combining fighter and monk) and hunter (combining druid and ranger). They are two of the classes I see the least point to in the entire book, the hunter in particular. In many ways, a ranger is already like a fighter/druid combination, so to then combine it with druid again seems like overkill. Hunters are very focused on their animal companions, but this is something that could easily be handled with ranger or druid archetypes.
The next two classes are among the more interesting classes in the book. The investigator combines alchemist and rogue, while the shaman combines oracle and witch. Rogue and alchemist are not two classes I would have thought to combine to create an investigator-type character, but the combination works pretty well. The shaman stands out as being a little bit more than just a combination of its parent classes. Every shaman has a spirit animal, which works similarly to a familiar and is the source of the shaman's spells. A shaman must also choose a spirit (separate from the spirit animal), which works like an oracle's mystery. The spirit determines what hexes the shaman has access to. Even though oracles are spontaneous casters and witches are prepared casters, shamans don't use the system that arcanists use to cast spells. Instead, they are simply prepared casters. The shaman class combines the abilities of its parent classes in a really interesting way that manages to carve out a bit of a unique niche for the class. For this reason, it's one class that I might consider allowing in my games.
Following the shaman is the skald (barbarian/bard), and then the slayer (ranger/rogue). The skald's raging song ability (which lets the skald's allies use the barbarian rage ability) is an interesting ability, but one that I feel would work better as a bard archetype ability. The slayer comes across in some ways as a non-prestige version of the assassin prestige class. In place of the ranger's favoured enemy ability, slayers get a studied target. By studying their opponents, slayers gain bonuses equivalent to the favoured enemy bonuses. As studied target is really just a variant favoured enemy, I really don't see why it couldn't just be another archetype ability.
My favourite class in the book is the swashbuckler, which is a combination of fighter and gunslinger. Despite having gunslinger as a parent class, however, swashbucklers are not necessarily gun users, opening the class up to people who don't like guns in their fantasy games. Swashbucklers don't gain firearm proficiency, for example (unless they take a feat for it, of course). What connects swashbucklers to the gunslinger class is their panache ability—an ability that I absolutely love the flavour of. Panache works like the gunslinger's grit ability, except that it applies to light or one-handed piercing mêlée weapons instead of firearms, making panache somewhat more versatile than grit. Swashbucklers learn deeds that they can use their panache with. These deeds include things like kip-up, menacing swordplay, and dizzying defence. While I think there are other ways to create a swashbuckling-style (there is already at least one swashbuckler archetype in the game), this particular swashbuckler definitely has a flair all its own. Of all the classes in the book, it's the one I'm most likely to use in my games.
The last of the ten new classes is the warpriest, a combination of cleric and fighter. This class joins the brawler and hunter as the classes that have the least point of all the classes in the book. Clerics are already essentially warpriests, so warpriests have absolutely no niche of their own to fill. They have the same base attack progression as clerics, but gain a few additional options to boost their combat abilities. In return, their spellcasting progression is reduced. The overall effect is just a cleric with slightly different abilities.
It is in the later chapters of the book that I hoped to find more things of use to me, and to a small extent, I did—just not as much as I'd hoped for. The second chapter is on archetypes. There are archetypes for every class in the Patfhinder RPG, not just the ones in this book. However, classes from other books only get a single page each (meaning only one or two archetypes), while the new classes get several pages. This is fully understandable as the old classes have had many archetypes published for them already, while the new ones have only this book. Nevertheless, if I'm not using many (or even any) of the new classes, I'm not going to get much use out or archetypes for them either.
The archetypes for the older classes generally focus on providing those classes with one or two abilities from the new classes in this book, fitting the book's theme of multiclassing without multiclassing. The inspired chemist (an alchemist archetype), for example, gains a few investigator abilities, while the sacred huntsmaster (an inquisitor archetype) gains a hunter's animal companion in place of judgements. Several archetypes provide access to panache-like abilities, allowing numerous types of characters to benefit from this rather fun ability. On the whole, I rather like the archetypes—partly because, as I've said more than a few times, I think most of the classes really should have been archetypes in the first place. If you're going to multiclass without multiclassing, archetypes are the best way to achieve it.
The third chapter introduces lots of new feats. Keeping with the book's theme, many of these feats grant characters an ability of another class. This, I'm not fond of. Generally, it's a lesser version of the ability (Believer's Hands, for example, grants you a paladin's lay on hands ability, but only once per day), but not always (Divine Protection just flat out grants you a paladin's divine grace ability, something very potent for Charisma-based characters like bards and sorcerers). However, even when it's just a lesser ability, allowing feats to grant class abilities makes one wonder what the point of having classes is to begin with. Might as well just have a classless system and let feats determine all your abilities. There's nothing wrong with classless game systems (indeed, there are some very good ones out there), but Pathfinder isn't classless. There should be limits to your ability to “pick and choose”.
The next two chapters are much more useful. The fourth, the spells chapter, contains spells for every class, and very few are for only one or more of the new classes. A lot of them are very flavourful (like whip of spiders) or have uses for things not previously covered in the game (such as speak with haunt). Of course, there are a lot of spells in the game already, so these spells are going to be limited in their use just from the sheer amount of competition. Chapter Five contains new gear and magic items—again, things that the game already has a lot of, but having more doesn't hurt.
The final chapter contains advice on how to create classes of your own. This isn't a codified rules system like the race creation rules in the Advanced Race Guide. Rather, it is a set of guidelines to consider when creating new classes. The chapter also contains advice on creating archetypes and prestige classes, along with advice on how to decide which of the three things your new idea should be. Even though I'm not overly fond of the new classes in this book, this chapter is well-written and the advice is useful. Indeed, I think the book's designers ignored their own advice when designing the new classes, this line in particular: “If the class you want to design is very close in concept to an existing class, with just a few variations, you might want to investigate creating it as an archetype instead” (p. 240).
On the whole, I don't think the Advanced Class Guide is a terrible book. In fact, I know it's the kind of book a lot of people who don't like Pathfinder mutliclass rules will want. However, to me, the new classes (with the possible exceptions of the shaman and swashbuckler) just don't have enough of a unique identity to justify being entirely new classes. I feel I can emulate most of them with the existing multiclass rules (and maybe some archetypes) quite easily. This ultimately makes the book of little use to me, as there's no place or need for the classes in my game.