I've been pretty happy with Vicurex. It doesn't have the massive amount of various alt coins that Cryptsy has. However, in my mind this is a good thing. Focusing on a more select, group of coins, and in smaller volumes, suggests to me a more careful approach, with less potential for issues. However, as my volumes keep increasing, I may eventually need to look elsewhere, but I'll stick around as long as they keep meeting my needs.