TWU - Houston, for one is much more expensive, and the cost of living if you want to live near the school and stay out of crazy traffic is also pricey! TWU is more research based than any other OT program in Texas, so if you are more interested in research I would say go to TWU-Houston. They also have a reputation of being a little more (up-tight) just because they have been around the longest and are highly ranked.
UTMB is an awesome program and the faculty and staff are very friendly. It is also ranked high as well. The program is much more laid back and you do research, but not as structured as TWU-Houston. Cost of living is also a little pricey, but not as bad as downtown houston.
I turned TWU down right away just because I am in no way shape of form wanting to do more research than I absolutely have to! I hope this helps!