I've not had a chance to run a game yet (I"m still trying to get my group to sit still long enough to honor a playtesting commitment!) but I have been using it heavily.
My own campaign world has been in development for some time, and there is definitely some crossover; I've been strip mining it for usable mechanics. I'm also injecting some of the flavor into a couple of arabic-themed cultures.
I did have a chance to play through the True20 adaptation of "Death and Freeport" as a player; we used weaving as a core ability for a bard class - that's been really excellent. We've also adopted a couple of the powers.
Our biggest criticism was that too many of the feats have way too many preqs - aside from that niggling detail, it's an enjoyable read with a staggering array of innovative mechanics and pitch-perfect style. I liked it.