There are only 2 dive operators on Brac (Scuba Shack and Reef Divers) and both have good reputations and loyal followers. We like to stay at the (newly renamed) Cayman Brac Beach Resort and dive with Reef Divers. CBBR is a small, diver-dedicated all-inclusive resort. We have been there 4 times.
It is a very nice resort with an excellent dive operation that provides full valet services at no additional charge. The resort food is buffet style but very good. They've just completed some major renovations including a big new freeform pool and a multi-level beach bar. Here is the link to their current specials, the price includes taxes and hotel services but not the divemaster tips.
Cayman Islands All Inclusive | Cayman Islands Vacations
One of the reasons we like to go to an all-inclusive on Brac is because there are not many restaurants on CB but the Captain's Table is okay. If you stay in a condo be aware that the grocery stores are small and often have limited selections because the supply barge only comes in once per week.
Cayman Brac is small and rural and there is not a lot to do unless you enjoy outdoor activities. You can go hiking and biking and climbing and bird-watching and visit the caves. You can also spend some quality time in a hammock by the beach or making friends around the beach bar or in the pool!
I understand that there is good shore diving and snorkeling but we have never tried it. The CBBR offers nightly entertainments like movie night and trivia night and a great barbeque on Fridays. Believe it or not Bingo night is very popular and everyone gets into it including the guests, locals, and staff. The resort has a small gym and a small spa. We usually rent a car for one day to explore the island. The rest of the time we walk or bike (or lay in a hammock or spend time at the bar!)
The diving is among the best in the Caribbean IMO, it is better than Grand Cayman but not as good as Little Cayman. The reefs are close with short boat rides. You will see beautiful walls, healthy reefs, lots of groupers, turtles, rays, eels, tarpons, a few sharks, and many tropical fish. There is also a sunken Russian Frigate that makes a nice, easy, interesting wreck dive.
The water will probably be in the upper 70s or 80 in March. You usually get 3 dives per day with possibly 2 night dives per week. Reef Divers offers a day trip to Little Cayman and Bloody Bay Wall for an extra charge (only if the weather permits and several guests are interested - it's worth the price!)
You fly to Cayman Brac from Grand Cayman on Cayman Air and they offer 3 levels of transport: a jet, a turboprop, or a small Twin Otter propeller plane.
Here is the link to an article I posted on Trip Advisor about the differences between the 3 Cayman islands, have fun!
The differences (for a diver) between the 3 Cayman islands - Cayman Islands Forum - TripAdvisor
---------- Post added January 5th, 2016 at 09:18 PM ----------
Here are links to a couple of articles you might enjoy:
Cayman Brac:
Journey to Cayman Brac
Cayman Brac free tours:
The Free Tour You Can't Miss on Cayman Brac | Islands