Mesa Grill certainly isn't Tex-Mex. It's Bobby-NYC Style interpretation of SW (which doesn't really exist).

But it's darn good... I have tried some of his recipes and have knocked the ball out of the park on a few, like Thai Red Curry Mussells. You can make a 7 pound pot of those for under $30 and feed a dozen people whom will be quite impressed...
I have my own recipe that I modifed from his to make it even more authentic Thai, if anyone wants to try it....