I don't think you can go wrong with Nikko if you're looking for quality sushi.
1. The food is outstanding. A lot of different rolls available on their sushi menu and interesting specials every time I've been. I haven't tried any of their teriyaki dishes or the bento box, but I've heard from others that both are great.
2. The wait staff is great. Have never had a problem with service.
3. Good with large groups. I've been to both the South Blvd. and Ballantyne location with groups of 12+ and never had a problem. Checks were always separated appropriately and no orders were messed up.
The only recommendation I have is to make sure you make reservations (if you can, I'm not sure about this...). I went with a date on a Thursday night and ended up with a 30 minute wait.