Can't say enough good things about Sushi Ko. A regular group from work and I go at least once a week and sometimes as much as 3 times a week for lunch. The specials are great and the quality of the food is always excellent.
If you are looking for a glam-type of sushi bar that serves dozens of western rolls then go to Ra.... but if you want tasty, reasonably priced AUTHENTIC sushi then Sushi Ko is the place!