Just my opinion ... but.. I left Java Black Belt. NOT at ALL because it wasn't any good. Rather, because you reach a point where you can't progress if you don't earn points, you can't earn points without evaluating questions or creating questions and I never felt qualified to do either. I was just looking for a place to test my knowledge and find holes in it.
SCJP - 86% - June 11, 2009
I used Java Black Belt, and they have some decent SCJP mocks there as well.
I think you'll be glad to know that they've got rid of their old progression style and now you can progress without them points, BUT only a specific order of exams. It's a good site and gives plenty to learn from.