I guess it depends on how well you know the particular NTB and whether you trust them to not mess up your car. As with anything else, you get what you pay for.
I'm going to try out Pro Tuning Performance out in fort worth (
Pro Tuning Performance - Dallas Fort Worth's Premier Road Race Performance Center - Homepage). They have top notch equipment and their prices aren't bad.
But for Houston, I'd probably go to Baker tuning so at least you have some piece of mind.