I've been to TCI 3 times and I have had 3 very different experiences (all of them were great, just different).
The first time I went, I stayed in Provo and dove with Dive Provo. It was a very well run shop that makes life almost as easy as if you were on a Live Aboard. You meet in the morning in their parking lot and they take you to the boat. After you have done 2 dives, you come back. You leave everything except your mask, fins & snorkel (and camera if you have one) on the boat and overnight, they will rinse and dry your gear. Your wetsuit and dive bag will be on the boat waiting for you the next morning when you get there.
The second time I dove in TCI, it was on the Turks and Caicos Explorer. As with all live aboards, the diving, the crew, and the food were great. Many of the dive sites that we hit were ones that I had done before with Dive Provo, but we were able to venture out a bit farther. For some reason, this trip was very "sharky". We saw reef sharks on at least one dive almost every day.
The last time I was in TCI, I went to Grand Turk and stayed at a resort called Bohio. Bohio is run (owned) by a couple of Canadian ex-pats and they very much cater to divers. (Their motto is "Just Breathe".) The dive boat picks you up on the beach right at the hotel. Most of the dive sites are so close that you get into your wetsuit before you get on the boat because there wouldn't be time to gear up before they "open the pool" if you didn't. I was there in March 2016, and I saw more turtles in 7 days of diving than I had seen in my previous 20 years! It was not uncommon to see up to 5 in any given dive, and it was uncommon not to see at least one. The whales were migrating through, and although we didn't see any while diving, we could hear them almost every dive. Much like the experience at Dive Provo, we would leave our gear on the boat, and the crew would bring it up & rinse it out and it would be waiting for us on the boat the next morning.
All three of these options were amazing, and I would recommend any of them.