I'm not sure what Miguel's is like, but I can make some suggestions for authentic and great tasting Mexican food in the Phx Metro area.
Los Picos in Mesa - Fantastic little family place that serves the best hand squeezed Colima Lime Margaritas I have ever tasted. I have tried just about everything on the menu, and it's all wonderful. Their Tioponcho Pork is their signature dish, and I would highly suggest it. It's Nayarit style Mexican, so it's a bit different than most of the other places here (most others serve Sonoran style.
Los Dos Molinos in Mesa and Phx - New Mexican Style Mexican food. Lots of green chili items, and everything is HOT, I mean HOT!!!!
Carolina's in South Phoenix - Old school Mexican Food with a cult like following. They make the best tortillas in the whole world! Not just my opinion, they get voted the best every year by the local papers. Very inexpensive and large menu.
Sylvia's La Canasta in Phoenix - Several locations. Family style Sonoran food with locations ranging from small taco stand to nice sit down restaraunt. She has a great cookbook out, and you can pick it up at some of the locations for much less than buying in a store.
These are only a few of the great Mexican Food places out here, if you are looking for a particular dish or style of Mexican food, let me know and I will see what I can come up with.
I hope this helps!