I liked Sushi D, but I didn't fall in love.
The sushi and maki rolls were disappointing. The rice was sticky and they put way too much for my taste. Your probably better off, ordering sashimi with a side order of rice so you can achieve the best rice to fish ratio. Oh, and they put cream cheese in some sushi rolls which grosses me out.
I recommend trying some other non-sushi items from the menu.
The Spicy Tuna Tataki is awesome (its seasonal, but they say you are limited to one order per table.) Try the rock shrimp, beef teriyaki, tempura shrimp, and the Korean Bbq ribs.
They were out of Soft Shell Crab, Fried Oyster, and some other stuff when I went. So that took away from the experience.
The quality is just ok, its what you expect from an all-you can eat place. I've eaten at better all you can eat places though.