My best advice is to stay at the Presidente (easily the most expensive and luxurious hotel on the island, VERY NICE! We've been there 4 times!) and dive with Living Underwater, a relatively newcomer on the scene. It is owned by a former DM with Aldora Divers (Oracio) and they use the steel 95's and 120's, but do not warrant a change in the din connection. They are fabulous! Oracio and Gabriel can find ANYTHING UNDERWATER! You may pay a little more for LU but it is definately worth it. The Presidente is always running deals but beware they are not including the on-site dive op (Scuba Du-they're OK, but after diving with LU) there is just no comparison. I don't recommend any all-inclusives as what is the purpose of going to Cozumel without sampling all the wonderful food options. I do not recommend trying to stay cheap, because you get what you pay for and if your spouse wants luxury, cheap is NOT the way to go! Good luck!