If you are going to the type of hotels that pdc offers and don't care where you go, then go pdc. For years cozumel was mostly divers place. Recent years brought in other travelers too.
Hotels there are older.
If you choose between the all inclusives you have Paradesis, which is older and has beach but not very nice water in front. Unless you want to go to a hotel that is not all inclusive, and you definately want to go to Cozumel, the El Cozumeleno is not such a bad choice then. The hotel is newer and food not gourmet but usually edible. Cozumel is not a fancy place. If I did not want to see Cozumel or dive, I would probably go to another location.