I love going to Pittsburgh, and every time my girl and I go, regardless of where we're staying, we always find time to make a trip to Hemingway's.
Granted, we're the 30-sommethings hanging out in a college bar, but the clientele always appeared to be pretty friendly (although we go in the summer when most of the students have left), the staff is very polite and accommodating, and the drinks are super cheap. For a proclaimed dive bar, the food isn't that bad either.
There isn't much to not like about this place, and that's why we keep going back.