I can only speak for Cayman Brac for direct experience from two previous trips, and Little Cayman through research and planning for a trip there this September. What is typical at resorts like Divi Tiara and Cayman Brac Beach Resort on CB and Little Cayman beach Resort on LC is to have a package set up as all inclusive with 2 dives per day and 1-2 night dives during the week. Adding the 3rd dive in the afternoon is an additional expense or you can go elsewhere and shore dive or snorkel. Sometimes they do offer 3 dive all-inclusive packages as a part of the specials, but most of the special deals are 2 dives/day. What I will say is that if you don't wait for a "special", the Caymans are indeed quite expensive if you are paying full regular rates. But they typically almost always have some offer or another going that gives a significant discount off of the regular rates. I think the biggest difference for you between GC and Brac or LC would be the pace. In general, the boats will be less crowded, the crew a little more laid back (but extremely professional and safety conscious), and the general pace a little slower and less rushed.
I sat down and tried to compare "comparable" diving packages at Coz and on Cayman Brac before my last trip to CB. What I mean by that is that when I dive, I want a clean, comfortable hotel room, I want the option to either have good food included in my package or available at a reasonably close by location, and I want an excellent dive operator with clean, safe, fast boats with ample room for however many divers they will put on them (preferably not very many).
What I figured out was this. I can go to CB during their "Splash" specials for about $1200, including airfare from Houston, 2 dives per day, all meals (great food), a nice clean room with air conditioning and a nice view, a nice white sand beach with hammocks under the palms, excellent 46? foot boats with twin diesels that are run by extremely safety conscious crews that do an excellent job taking care of your every need and making sure that your touch your gear as little as possible. (You set up your gear once on the boat, for the rest of the week, it is cleaned and setup for you, you sit at the back and it is brought to you and you are helped into it, then you stand up and giant stride in. I don't have to include in that price taxi fare to town, time and effort to go into town and find a restaurant that isn't packed with pod people, or the price for whatever meal I choose to eat. I also don't have to factor in staying in a hotel that may or may not have a view of something besides the highway, may or may not have direct access to the water, or may or may not have any semblence of a relaxing place to hang out post dive.
At Coz by comparison, I can get air from IAH for about $500 on a good day, a "comparable" quality accomodation will easily run $4-500 for the week with the dive op included (usually a cattle boat operation offering 2 dives per day). If I want to upgrade to a faster boat with a (possibly) more experienced crew, then I can count on paying at least $150-200 more for the week, and I haven't even factored in cab fare to get to town, the cost of meals, or any other non-monetary value for the lost time and lack of convenience. By the time all of that is factored in, CB is better diving (IMHO) and it costs at least the same if not less than Coz. Add in no language barrier, and no pod people, and I see no comparison whatsoever between the two that could justify calling CB expensive and Coz a bargain destination.
I recognize that for others, getting to Coz is cheaper than from Houston, and I also realize that to others, the atmosphere of San Miguel is more interesting than the empty beach on CB. I also realize that others think any room with four walls and a roof is an acceptable diving accomodation. There are times when I agree, but in comparing apples to apples, CB wins the comparison hands down. To me, the "Vacation" dive trip is different than the quickie 3-4 day long weekend. The "Vacation" trip means diving alot, doing as little as possible otherwise, touching the wallet as litttle as possible, and not dealing with teeming crowds whenever possible. CB and LC are where I will probably take my "Vacation" trips for the foreseeable future, unless we decide to go to the South Pacific sometime in the next few years.
