Having recently moved to Pittsburgh from San Francisco/Bay Area, it's good to find a place that fills that special niche of places that serve Burritos with tofu as an optional filling. I've been to Mad Mex three times now and each time it has been good. I can't speak to the meat dishes, but the Mad Mex Burrito and Spicy Mad Mex Burrito (both with Marinated Tofu) were delicious, as was the Herbovore Tofu Taco.
I was a bit disappointed by the salsa that came with the tortilla chips. It was too thick and had a strange smokey taste to it, but I can forgive Mad Mex for that, because everything else was good.
Pittsburgh still seems to be missing a good authentic Mexican place that serves up a burrito like you can find in the Mission in SF or pretty much anywhere in CA, but Mad Mex fills its niche nicely.