I just bought 2 more brushes from Mystikel at Renderosity, and I thought I'd give her a shout out. Her real name is Kelly Thompson, and I have had nothing but good results from her products. I own the following brush sets from her:
And I just purchased Impasto and Scratched. I guess I'm a Mystikel addict :) But I have loved everything I've bought from her.
You can find her Renderosity storefront here. Worth every penny!