I'm mildly thumbs down. There's some stuff I really like, and there's some stuff I really don't like.
Likes
Rogues as Swashbucklers
Tieflings
NPCs are easy to make
defined monster roles (bruiser/asassin/etc)
Dislikes
Dragonborn
Stupid feat names
the new FR
missing monsters (frost giant,etc)...
I also think MM3 was the best MM besides the main book. IV was HORRIBLE. Didn't get V, as I had a very strong feeling 4e was coming, and I immediately quit buying d20 books.
Unfortunately, DnD has become very complex. I'm hoping 4e cuts down on this severely. I really think 3e is at the point where it's scaring away more people than getting them to play. When I look at my Basic/Expert and 1e books, they aren't even half as complicated.
It's my favorite iteration of d20. But I really wish I could make a couple changes to the base rules as published, instead of my small stack of houserules. ;)
I recommend Frostburn, Fiendish Codex I, and MM III.
d20 wise: Arms & Armor, Penumbra Fantasy Bestiary, The Book of Fiends, and the Wilderlands of High Fantasy box set.
Guys, it's FANTASY! I WANT to see hot, near-to-totally nude women. If you must have a realistic look to your adventurers, feel free. But don't expect me to buy your book if it's full of ugly people.