I wasn't originally going to pick up the 4th Edition Player's Handbook 3. My DM is not using the new Hybrid rules and we both felt that the Skill Powers were neat as an idea, but not something either of us would use. Plus I was not thrilled with any of the new races (we now have animal, vegetable and mineral) and two of the psionic classes.
The book is cool for a few things. First off the Monk is just way cool. The type of game that D&D 4 is now the monk just fits right in. More so even that it did in any previous version of the game (especially 2nd Ed). It has a different flavor than the 3.x monk. Adding the Githzeri is just the icing on the cake there. Can't wait to try out a Githzeri cenobite. I will need to rework my whole "Monks are from Blackmoor" ideas.
I also like the inclusion of the Far Realm stuff as a reason for Psionics. Right up my alley. If the Far Realm is supposed to be the Cthulhoid alien/gods from Beyond then that is pretty awesome stuff. Of course I do the same thing in my WitchCraft RPG games. Plus the cool thing with this and the Githzeri is you can imagine the Githzeri on their lonely outposts fighting off the minions of the Far Realm/Mad Gods.
The Hybrid stuff is still nice. Been doing that for a bit though. There are some nice ideas on good hybird choices. Most is no brainer stuff, but still nice to see. I am working on a Dragonborn Monk/Sorcerer hybrid now just to see how it works.
The Skill Powers are neater than I gave them credit for at first. A nice way to customize each character.
There is still a lot here I am not going to use. The Psionics stuff is neat, but I never liked to mix psionics and magic all that much. The Minotaur are ok and since I just added Ansalon to my world I know where they come from now. But in a world with Goliaths and Half-Orcs and Dragonborn the niche they fill is kind of taken.
I now count 25 classes (which includes the Assassin) and over 30 races (more if you get creative with the Monster Manuals). That's a lot. Maybe even too much. I'll have to set some limits in my own 4e games.
The art is still fantastic and I only saw a couple of reused pieces. More as I read more.