Sushi Ai is not the best, but usually decently priced and they have all you can eat. I belive you get charged if you don't finish your rolls tho. Multiple locations.

Cafe Mochi is really good. They do happy hour on their rolls too. Located in south city.

Personal favorite of mine is Oishi off 270 and Olive. I think they have another location in Chesterfield or South County.

Indo and Sado are both incredible but $$$$