Pittsburgh has a weird vibe to it. Pretty much everybody that lives there is surprised by how much they like it (including myself) and aren't eager to leave, but once you have left there's just very little desire to go back. I have lived in many places (including other countries), and that's the only city that I didn't want to leave but also don't want to go back to.

Basically it's nice enough to be comfortable, but not great enough to be desirable.