I was just banded (same group as XAnn) by RR's group. I was acquainted with him from high school days - and based on those hazy recollections, I expected him to be very good. He has probably as much or more experience with this procedure as anyone else in the western hemisphere; he is, and has been for years, active in training other surgeons in the procedure. I had a great experience, and think he did a good job, although, well, I was anesthetized, so I couldn't watch. He has a good team in place, and even has e-mail follow-up nutritional advice. Finally, he's a straightforward, approachable sort, with a very appealing bedside manner.
Although the hospital he uses is very modern and nice, Monterrey is still in Mexico - while it is in part a wealthy city, there is tremendous disparity, with many poor as well (just not in the part of the city we were in). I would advise going to Mexico with an open mind - not everything is done in quite the same way, and a little effort on the visitor's part goes a long way. Also, the museum is closed on mondays, and you probably won't feel like walking around too much the first day or two post-op.