The Mad Mex restaurants are one of the more consistently popular chains within Pittsburgh.
For dinner, this one always seems to be packed, no matter the day of the week. It's a small, pretty crowded space. And they pack 'em in! You can't squeeze through without bumping other patrons. Service is hit or miss, regardless of whether it's crowded. I've had fast and really slooww wait times for food.
The ambiance is pretty fun though. The beer selection is decent and the margaritas are fantastic. I don't think I've ever been truly disappointed or blown away by the food itself. There's lots of different offerings but the flavors in each entree sort of melt together and don't stick out too much. Nothing to get too excited about. I've continued to come back here over the years though because it's a fun place, if you don't mind the crowds.