We stayed at TIL March 07. We did three dives a day, except the day before our trip to the Blue Hole and the last day before we left. So we did a total of 16 dives. If you like a remote, relaxing dive trip, short boat rides, great diving, excellent homemade meals, and good service - TIL is well worth it. You can also search by "Turneffe Island Lodge" - I posted something right after our trip on the board.
I hear Little Cayman has spectacular diving, but haven't been yet. We're already booked for Conch Club, LC in March 08.
Either way, you probably can't go wrong.