Had a great time on the Aquaboats. Pretty adventerous and high speed, so good way to avoid kids and crowds. Disney shore excursion prices actually seemed less than what we've seen on other lines.
Costa Maya is clean, organized, shopping area with a few overpriced bars, restaurants. Would recommend a tour, or cab to town for snorkeling and cheaper drinks.
Disney Magic docks downtown, unlike larger ships, so perfect for shopping and wandering around. Cozumel is great stop, just ignore the constant vendors and hawkers. Or take a cab to Playa Corona, great close by beach and bar.
More 
