Just went there tonight for a birthday dinner. Our reservation was at 6:30 PM and we sat down about 6:40 PM. The service was extremely slow. We didn't even get our food until 8:00 PM. When we told our waitress nicely how disappointed we were at how long everything took she proceeded to give us excuse after excuse about why our food took so long, but never an apology. She told us the manager was on vacation (we didn't even ask) and that the owner was there. However, the owner never even came by the table to apologize or try to smooth things over. It seemed like they could care less that we were having a bad experience.
None of our food was bad, but nothing was exceptional either. I ordered the Ensalada Del Sol and it was not very good. Very skimpy on the vegetables (it's a salad!). However, the guacamole dressing is very good.
Overall, I would recommend going to a different mexican restaurant. There are many other great options in the Madison Area -- restaurants who will appreciate your business and do whatever they can to make sure you come back again.