I've been to both and am heading back to Grand Cayman next week. Access to dive ops: Cayman probably wins here. They are both set up so that you (mostly) need to stay with one op. Curacao gives you the dive-where-you-like option to a greater extent IMO. If you say "access to shore dive sites, Curacao wins. They are hard to get to but there seem to be more choices along the island. Good snorkeling: Cayman probably wins here. Near the hotels is good in Curacao, Cayman has Devils Grotto area and some others that are exceptional. Nice beach: You can't beat the sand or service on seven mile beach in GC. The water in cayman is 85 degrees right now. I found Curacao to be a bit colder. Viz: Both are the same IMO, perhaps a bit more in Cayman. Flights: Cayman seems easier to get flights and less expensive right now but that depends on how you book. Cost of stay: I definitely found Curacao to be less expensive to stay. It does depend on where you are though. I am on 7 mile beach this trip to GC and the stay is more than twice the flight cost. It may be a wash honestly. Where to stay: On GC, you need to be near 7 Mile Beach. I stayed at Sunset house the first trip and that was awesome. On curacao, I stayed up north which was far from town but I had a car because I was doing shore dives. I would probably recommend staying in town at one of the big hotels. It's closer to the night life and shopping. If you want cheap accommodations, I think it is more likely on Curacao. Diving: You didn't mention diving and I can tell you it is different. Cayman - walls, lots of fish, can be deep, some wrecks, competition from dive ops. Curacao - many shore dives, colder water, sloping ledges and double reefs, more independence and choices, one cool wreck. Hope this helps. PM me if you want details.