I got back from Playa at the end of August, beginning of September. I can wholeheartedly recommend Abyss Dive Shop for fully-professional staff with the right attitude. The several dives that I went on were well briefed, we were dropped right on target, the divemasters were knowledgable, and helpful on top of it all. One heartwarming bit of trivia, they fail people on checkout dives -- thank you for not passing everyone just because...
Gotta dive Tortugas for just what you would expect, Tortugas...
I can also recommend La Rana Cansada as a place to stay, less than two blocks from the beach, "premium rustic" rooms, and the best staff you can imagine. Babe's has the best food (noodles) in town, and Java Joe's is the place for coffee.
I'm not back there right now as it is hurricane season. Would be a great time to go if you didn't expect to dive every day. If you're there in early December, look me up!
Drop me a line if you need any more info!