I got one via them because our connection keeps droppping? We didn't pay, and it also took 4 months to arrive - but it also hasn't helped us any.
If your're looking for a booster, ask them what your problems could be before you pay for one. We were told that our connection was dropping because the 'modem was getting confused between two beacon signals'.
I've bought the PA-12-YAGI yagi antenna. I don't know if they all work with iBurst. I called them and explained that I had the UTD. They recommended this antenna. Not sure all the yagi's will work, as they're normally designed for a specific frequency range.