We have been to both and LOVED both....I always said that Grand Cayman had the most beaustiful beaches I've ever seen - the sand is like cream of wheat...I've never felt sand like that anywhere and we have been to just about every Island in the caribean. It is expensive to eat out in Grand Cayman...maybe alittle more than Aruba, and I felt that the people working there were not as friendly as the staff in Aruba (most of the staff in the Cayman's are from England)-they do not dote on the tourists like they do in Aruba or Mexico-that was my experience...it was 9 years ago....so it could have changed=but I still would go back. Also-the scuba diving is amazing!!!!