I definitely recommend the Hotel Cozumel/AI. I don't know the ranking but I give HC a solid 3 stars Dive Hotel, clean, convenient, staff are pleasant. You meet a lot of divers, and people often show video or photos from the days dives on the lobby bar tv. The AI saves time in the morning and if you dive w Dive Paradise, you can have lunch while your gear dries next to the beach. Actually, you can use many different dive ops. We were always happy with breakfast and lunch, nevermind the convenience/lazy factor, and usually dinner (you could always poke your head in to see the dinner buffet)
Shop around tho, as long as you get a good deal you don't feel guilty eating dinner out in town. I'm sure there will be days you are whipped and eat dinner at the hotel tho.
We just used Bookit.com, a 99 hour special, and got air/hotel/AI from NJ for $820 pp total ( that incl tax and fees).
Check with DP ref the night dive tho, I think you may not be able to use them for a night beach dive as the shop closes. They and other dive ops do night boat dives.
Bring a wad of singles (or bigger bills) and tip the staff! Good Luck.