Having done TCI for the past few years, I would recommend going somewhere else. TCI is a great place, the ocean and dive sites are amazing, but sadly over the past few years the overall quality has declined.
Far fewer fish on the reefs...very few large groupers, and a decline in the smaller reef fish as well, very few sharks, very few turtles. Overall the feedback from the dive guides has been that the past few years has been tough for diving at TCI. One suspect is the lion fish, the other suspect is over fishing.
I don't mean to dump on TCI, as we have many great memories and lots of great dives there, but I do feel like the area is in decline over the past few years.