zaf88,
Been to the Cayman's a few times, can't comment on where your staying except that I've heard people seem to like Aqua Bay Club. Have walked by the Casa Caribe but can't remember it off-hand.
Bob Soto is OK, not great. Depends on your experience level as well. I think the best diving is on the East End but it tends to get a little rougher at times as well. Ocean Frontiers was my favorite followed by DiveTech. Ocean Frontiers will pick you up and drop you off for morning dives even though you are on Seven Mile Beach, about a 45 minute ride. They will probably cost more but I think are a better operation. Bob Soto tends to be alot more divers and more restrictive, but then again when you have divers of varying skill level I'm sure it isn't easy. Alot just depends on who the divemasters are on the boat and that can be the luck of the draw.
Things to do... Turtle Farm (DiveTech is next door)... Lonestar Bar & Grill (favorite)... parasail... you can walk to town although a few miles but still walkable... fairly quiet island but depends what you like. Drew on this board lives there and if you search his posts you can get more input on dive operators and goings on...
Kev