If you like Sushi you should try Strip @ Atlantic Station http://www.h2sr.com/strip/, I just realized looking at their site that this resturaunt group also own Shout and Twist. I've never been to those but I know that the sushi at strip is similar to that of their other resturaunt in Lenox mall. So they may be similar. The sushi oddly enough is pretty damn good for a steak house, seriously. The real hidden treasure is the calamari in this place, you have to get the calamari appetizer!
Another option is Ru San's on Piedmont http://rusansmidtown.com/ The sushi here when ordered a'la carte is fresh and delicious. If you eat their buffet alot and order from the menu you can actually tell a slight difference in taste and quality..however as buffets go you can't get any better than Ru San's for sushi at 9.99 during lunch. The only other Sushi buffet I would recommend is Nori Nori and that's up in Sandy Springs and costs $25 per person on weekends, it's okay but for that amount of money per person you can eat like a king at Strip.