I think cowfish is overrated. There is always a long wait, they don't take reservations and there are way better sushi restaurants in Charlotte.
I do like the concept though, because if I can't make up my mind, there is always a way to get a little bit of both (the bento box is my hero, and is what I've ordered both times I've been to the cowfish because I get a little bit of burger, a little bit if sushi and I don't have to pick one or the other). Their sushi is fine, the burger is fine and I always leave satisfied.
Only three stars because I just don't think it's worth the wait.