Cozumel is worth a look if you are interested in drift diving. You said you like Grand Cayman partly becuase there is little current. Cozumel has plenty of current, but you adjust your diving style accordingly. Just go with the flow, let the current carry you along. The boat follows along and picks you up at the end of the dive. It's lazy man's diving. The reefs are incredible and the vis is pretty reliable in the 80-100 ft range, often over 100 ft. I have done some great night dives there, once saw seven octopuses on one dive on Paradise Reef, although I have not been back for a night dive since Hurricane Wilma. There is quite a bit to do on Cozumel if you are not diving. My wife went there with me twice before she started diving and loved it. It's easy to get to from most parts of the US and pretty inexpensive.