I just love Tachos, my family has been going here for quite some time now. Whenever I am in town visiting family this is one of the restaurants I like to hit up. The service is decent. I wouldn't say its the best cause they could us improvement.
One thing you do have to watch out for is that they don't add your tip to your bill. There was 8 of us one time, mind you that 2 of them were little kids, and they tacked on that 15% gratuity. (I tip well cause in Texas, you make 1/2 of minimum wage as a waiter, and the rest of your wages come in tips.) I would have probably given them more than 15% if they weren't trying to be get more for their service.
They have great lunch deals, so if you are looking for a cheap lunch this is the place to come. I never pay more than 8 bucks for lunch, with a drink and a tip.