Hana is a very small place; one of only two sushi places in Rapid City that I'm familiar with. There's not much to it. It has a very small dining area, and a tiny floor-seating area on a raised platform with only two tables. That's where I sit every time I go; I think it's fun to relax on the cushions without my shoes on.
Their korean food is great: flavors savory and nuanced. The sushi is average, and by that I mean that most sushi places have something they do best and Hana is no different. And what that thing is depends on what you prefer.
I like to share one korean dish and two sushi rolls with my companion. The food is presented well; the service speed is average.
Keep in mind that since it's so small, almost all of the seating area is fairly near the door and in the winter it can be drafty! Bring your jacket with you just in case, but the food is worth the trip!