Ok, now listen- I may be from NJ originally, but I've been a West Coast chica for 20 years now, and I KNOW from Mexican food, mmmkay?
La Pinata is THE place. I'm telling you. Try to supreme fajitas or the Chicken Chile Verde enchiladas...they'll knock your socks off.
Like tequila? Well, this place makes their own, plus they have (what looks like) about 300 other varieties to try, as well. THE BEST MARGARITAS I'VE EVER HAD. They have fresh fruit & sugar cane stalks in them!! I don't really even like tequila but I could drink an entire pitcher of their margs...except if I did that, I'd probably die because they're hella strong!
It is kind of hard to find a place in the East Bay (on the east side of the Caldecott tunnel) that serves amazing Mexican food but is an actual sit-down restaurant. (there are tons of taquerias but you dont necessarily want to go to one on date night...) We have finally found La Pinata, and I am happy to say I have been here about 10 times so far over the last 9 months. I have tried breakfast and lunch, and have had 100% consistently good food and pretty good service. I would say the service is occasionally a little lacking, but its a restaurant...remember that most of the people working there DON'T GET a regular hourly wage. Having been in the service industry in the past, I'm pretty lenient when it comes to those things. Sometimes its a tad fish-odorous when you first walk in, but I think that's because they serve A LOT of pescado (whole red snapper, fried).
Bottom line: Try this place before you try all others. It's WAY better then Maria Maria & about half the price.