Remember most people who are happy and not having problems do not post so much on these sites. A lot of posters on these sites are the ones with problems. It does not reflect the whole. Slippage and erosion happen in 1-2% of cases. Slippage usually occurs with vomiting and overeating. That is operator error in the case of overeating. Erosion happens for unknown reasons sometimes, and in others cases, it is doctor error. Doctors sometimes put more sutures into the stomach or suture the stomach too tight to the band. The more experienced the doctor the less likely to make those mistakes.
These sites are informal and rarely have anyone with expert advise on them. I would advise you to talk to your doctors and staff.