We have been coming to Cozumel for 35 years and have stayed everywhere. We started up north at Cabanas del Caribe (gone with Wilma) loved it but you had to have a car or taxi. We've stayed at Fiesta Americana(10 x before the reno) Iberrostar (5 x) Occidental Grand, Park Royal (10X) Casa del Mar, Blue Angel, Suites Bahia (3 x) Vista del Mar (3X) Cozumel Palace, Casa Mexicana (3X). We now go for 1 month 2 times a year and usually split 2 weeks in town in order to walk everywhere and hit the great restaurants. Then we stay at an AI for 2 weeks, since we have friends that come down and have non diving wives.
We have settled on Casa Mexicana as our in town hotel....great staff,breakfast, well priced. We stayed at Cozumel Palace for the AI part of our last trip (pricey, but we purchased the weeks from a Palace member) this last trip and we were really spoiled. We won't go back to the Southern Resorts. Just too far from town and costly cab ride.
We have dived with Dive with Martin, Aldora, Blue Angel, Blue XTSea, Living Underwater, Tres Pelicanos all great, but have settled on 3P. We get to see our friends (divemasters and owners of the other shops) on the surface interval at the pier.
Have fun
Cheryl