I always order Katsudon since I loved those growing up. Theirs isn't bad, depending on the cook I believe -- I've had it when it's flavorful and had it when it's bland. I'd still keep ordering it though if I do have a craving.
I tried their ramen. The tantan-men is spicy. A little bit too spicy for my taste. I tried the Hakata ramen and it wasn't bad. It just didn't blow me away either.
I'd still stop by if I do have a craving for Katsudon.