Fathead's is a Southside classic. They have local PA brews on tap, very large and delicious sandwiches and pretty good wings.
I've been here many times and the reason why I give it three stars versus four is because of consistency. The quality of the food varies in consistency as does the service.
On a good day, Fathead's is an easy 4. Some of their sandwiches, especially the spicy ones with habanero have some really unique (for Pittsburgh) and well thought-out flavor profiles. And their wings are also very good (Original Sauce is excellent) albeit not cheap. On top of that they also serve smoked wings, which may be the best way to eat wings in general. So the food can really be quite good.
It's just that in order to rise to a 4th star for me, repeat visits have to be at that level. So it's a very solid three, and I try my best not to succumb to grade inflation.
So if you like good beer, good food, big portions and really don't care about the service on any particular day, then go!