Mad Mex has been a staple of my life since college in the city. The Shadyside location is always quite busy but the size of the restaurant helps alleviate the wait times.
Food is almost always good. Wasn't terribly hungry this night so just ordered wings w San Fran sauce. Crispy wings and sweet/spicy balance on the sauce was excellent.
As always I feel the margaritas are the star attraction, even with the good food. Can't beat the half-price Big Azz ones late at night or during happy hour.
Always a recommended stop for a good drink, great atmosphere (though always very dark) and a solid menu.