Cazadores has pretty decent margaritas, too, or used to. I haven't been there in a few years...maybe it's time to go back.
WoMD, maybe Mi Cocina isn't very "authentic" Mexican, but I think it's at least more Mexican than it is Tex-Mex. And like all major cuisines, Mexican food varies pretty widely by region, so perhaps Mi Cocina's food is merely different from the Mexican that you're used to? (I don't mean to sound arrogant—I'm certainly no expert; it's just an idea.)
--
Bad grammar makes me [sic].