Don't expect anything gourmet and you will be fine. For me personally I absolutely love it, i've had the nachos and the combination platter and loved both, i just love the gooey mess that is chilli, salsa, and soured cream, throw some refried beans on and you're good to go. Its messy and yummy!
now as for San Angel Inn I definately felt ill and will never go back, didn't like the service, hated the meal, hated that it took so long for everything, and as you can tell I am not a fussy eater. I was so upset that I had given up my mexican counter service for that because frankly the Cantina food is so much nicer than San Angel!