We go to San Angel Inn once every trip as a traditional first meal on our first night at WDW.
Nine years ago if you had asked me this question I would have said average but overpriced mexican food, great atmosphere.
Every time since then the food has improved a lot. I would say it is above average food, prices are about the same (which is good), and there is something about the atmosphere that we all enjoy. We always make it a tradition to ride the Rio del Tiempo (boat ride) after or before our meal depending on the wait.
So, yes I would recommend it and the food is on par with many of the other good TS restaurants in Epcot (but not in the best category as Le Cellier, etc.).