Diving in Belize

Usually book indie dive ops in ports, but Royal Caribbean has dropped the price of an excursion to Turneffe Atol. Also, this dive is farther from shore, so most indie dive ops don't take cruisers there due to time constraints. RC excursion picks you up at the ship however, saving travel time. My question is this, how different from the Barrier Reef dives is the Turneffe dive? It is now just a little more expensive, and less hassle. More pelagics? Thanks!

I thought Turneffe Atoll was a part of the GBR, like Ambergris Caye and Lighthouse Reef (Blue Hole), the other two major atolls in Belize. It's the closest to Belize City. There are a couple or three resorts around. Has great reviews on dive sites. People usually fly there, so this might be a great opportunity to enjoy it without worrying about getting there and back.