I like it. I could go on and say why I like it, and I will. Customization, holy balls does this book let you do a lot of shit/crazy shit. the race supplied is incredibly customizable on its own, and I'd have bought a book for that as it provides plenty/endless avenues to make your own, personal race of beasties, in an much simpler/easy to understand and quicker than simply making a race on your own from scratch, by y choosing their diet and mobility type to construct their racial traits/attributes/stats, and with the amount here, you can as I said, make endless amounts of your own beastly dudes and duddettes to fill your world with and or play as. The various feats help add flavor and an extra dash of uniqueness or umph to your character. And just from that you can see the book is beautifully organized, and a far easier read than others I've encountered, with information sectioned clearly and so presented in an easily digestable way. The beast races you can create, even if you go wild aren't over or underpowered and would fit any pathfinder or 5e game well without breaking balance or shaking things up too much, and as I said, the feats are awesome.
then we come to the hybrid rules, which my god are just perfect. it is and expanded form of the beast race creation at the front of the book, and like those are easy to get into, and present even MORE options than they do, just a ridiculous amount. Even if you just had the basic races to work with it'd be a lot of options for half breed. Just with the featured races from pathfinder it'd be insane, but add in the more monsterous options of the physical qualities you select for you Halfbreed (you get two of these and one upbringing to make your hybrid, and most races have two kinds to split up their traits, which makes the sheer variety even more mind boggling), and these monsterous choices include such things as Owl bears, manticores, Aboleths and many more (seriously, those are some of the more mundane parentages you can select for you little abomination, in the monsterous section of hybrids), and you get so many options and mixtures that describing it would be hard, so I'm just going to say you have more than enough and endless ways to make your creativity and visions known (wanna mix dragon turtles and gnomes? well go right ahead you crazy person you). The upbringings that round out this creation start off normal, you know raised by so and so race, but then as it goes on you can get some really cool/ fluffy options (wanna have been raised by a dragon? A god? Want to be a wild child? a former slave? raised by kobolds? go right ahead, your halfblood can have been raised as or by any of those, or as previously mentioned be raised in much more mundane settings if you want). So the hybrid rules, well they're awesome, insane and have more options than you can shake a stick out or count. And, they aren't unbalanced, and wouldn't disrupt a game by falling behind or being massively OP. and the feats again add some awesome stuff to the table (my favourite being the one that gives you an additional Physical attribute/ heritage, as I am always one for playing weird freaks of nature/ monsterosities)
SO all in all, amazing book, simply fantastic. Might not be the longest, but it has two things I'd have bought entirely seperate books for if they were split and they are quality, so I am not bothered by its length, it fits more than books four times its size do in way of options/personalization/ and customization. And while I'd give my left kidney or leg for an expansion on these choices, I am VERY happy with what is already here, as I have mentioned so many times before, it is already so expansive.
Seriously if you have the cash, pick this book up, I know the cover may turn people off for being furry, but it really isn't at all and lets you play beastmen/anthros in a way that isn't creepy because of some guy injecting their fetishes into it
Same thing with its (very very loose) connection to ponyfinder, even if you froth at the mouth at there mere mention of the colorful horses, pick this book up, you can just ignore the one section of the book they're really mentioned in
TL:DR: this book is amazing, look past the cover if it bothers you. The hybridization rules here ARE NOT TO BE MISSED. Seriously, the book is worth it just for them