Dress is supposed to be business casual, which at Disney pretty much means no tank tops, cut offs, or bathing suits.
I ate there 2 weeks ago and most people were nicely dressed.
My whole family was disappointed with the experience. We had a very unfriendly waiter and none of us really liked our meals, except my husband, who got a vegetarian dish (can't remember what it was called). It was quite a contrast to California Grill, which was one of our best dining experiences ever.
Not too sure this is a place I'd take 3 young kids either. Boma would probably be more suitable.