As faculty/researcher it is a fantastic place to work because of the unique combination of quality and small size. This latter makes it easier to deal with the painful admistrative overhead that accompanies research (note that the actual overhead costs on grants are not as high as in many other places, but they still hurt).
Students are great, atmosphere is great, facilities are great, and I will add that Houston is great.
More than a "con" is an observation about what I felt is a mismatch between the talking and the "walking" for what concerns collegiality, loosely defined (probably the most used/abused word in every meeting/gathering/report). Everybody is quick and happy to fill his/her mouth with big self-congratulatory statements about collegiality, but in my experience the collegiality stops there.
It does not run very deep. That's been my experience. There is not a true spirit of being a "community", instead of just a cohabitation of researchers under the same roof. Dept. events (social, but also colloquia) tend to be poorly attended for instance, which I would consider a pretty genuine clue that people don't care that much about the rest or their department (and not just the divas).
Improvements have happened over time, slowly, but there is still a lot of room for improvement on faculty/instructors/postdoc mentoring. The older generation's faculty often seem to see it as a sign of weakness and there isn't yet a "culture" of the importance of mentoring and appreciation of its positive impact not just on mentees but on mentors themselves.