Los Sombreros is one of my favorite restaurants in the valley. The food is always just perfect. The prices are extremely reasonable. I modeled my own guacamole recipe after theirs, it's that good. Try the specials of the day, they're always great.
The service has been a little hit & miss for me. Most of the time they're fine. There's this one woman who is extremely unfriendly. I think she just doesn't like me :-) But ya know, with food & ambiance like this, it doesn't bother me if I occasionally end up with a cranky server!