I was there this past May and stayed at Banana Beach and did our diving with Ambergris Divers which Banana Beach lined us up with. I have been diving for 25 years and they were the best that I have ever dove with. They pick you up by boat in the front of the hotel and drop you off when over. In my limited experience in San Pedro, I thought Banana Beach was a great deal for cost.
Great Food, nice Beach, good people, etc.