We just spent Christmas 2017 in Grand Cayman. Stayed on the East end of the island for 12 nights and flew home Christmas afternoon. We dove (repeatedly) with Ocean Frontiers (highly recommended) at various wall dives on the East end. It's a bit windy this time of year but once you're 15'+ deep it doesn't matter. Best dive was our last at site named 'Rivers of Sand'. Starts at 60' depth and you swim through amazing pass throughs to the wall at 105'. The wall drops from there to over 2K feet...haha. Water clarity was over 100' making this a top dive site and a family recommend. The island is very expensive, makes San Diego look bargain, food/alcohol is easily 2-3x prices here, so even shopping at the store and cooking in the apartment is not trivial. The diving makes up for that. We don't plan to return to GC as there are many other dive locations we want to experience but we loved the trip and created great family memories there.
View from our 2nd floor residence (Wyndham Reef Resort).
For 2018 we plan to dive Belize.