Grabbed this while looking for some new and interesting Prestige Classes. While the classes are not bad at all, they didn't interest me all that that much. I will say though that if you are into thief-like prestige classes then this is a good choice. You get 8 new prestige classes and a handful of feats.
There is an OGL declaration in back, but the copyright information doesn't really mesh with it. I know that these sort of things should not affect my opinion, but they do.
For under 4 bucks though it is not a bad little book.