Truly great Tex-Mex?

It seems like a lot of the major names, Pappasitos/El Tiempo/Ninfas/Chuys have gone downhill of late, so I've been wondering who are the Tex Mex places that are still truly great. I've never been a huge Lupe Tortilla fan, and while places like Hugo's and Irma's are great, they don't exactly fill that niche of a place that just has good fajitas, queso, enchiladas, and margaritas. Any recs?