I dived with MDA for a week in December 2007. Thought they had a pretty nice operation. Prices were reasonable.
My only issue was that they wouldn't let me dive during the week unless I had a buddy with me. The boat was taken up mostly by Japanese tourists during the week (this is not a problem on weekends). They didn't feel that they could "guarantee" that I would have a buddy.
My friends (who ironically were Japanese
) were leaving to go back to Japan on an earlier flight so could not dive on the last day before the flight. I was faced with having no dive buddy that day.
Fortunately I ran into someone at the shop who we had met earlier while diving Gab Gab at the US Navy base. She offered to dive with me and I got two more dives in before I had to leave