IUI and PGD - Bumrungrad vs Superior ART

Hi

I've just recently had my cycles monitored and it's revealed that I release 2-3 mature eggs per cycle with a handful of smaller eggs. We are undergoing IUI (with PGD as well to try for a son as we have twin girls) but we are a bit stuck as to where to go in Bangkok. We are booked for end of December and have been in touch with Superior ART but they have not really put my mind at ease with their lack of communication and their vague responses. I have been to Bumrungrad before and they really impressed me, but they don't want to commit to seeing me over the weekend between Christmas and NY, but this is when my CD2 falls and I will need to start stimulation. We're very new to this whole procedure and not sure if we should just go with Superior ART or if there is something else we can try.

Any suggestions would be very welcome. Anyone dealt with Superior ART before? Are they professional? How do we find out their success rates etc?

Thank you in advance.