There are good things and not so good things about the 3 hotels you are considering. It just depends on what you are looking for as being important:
Distance to town:
Cozumel Palace: If you want to spend time in town and would like to be able to walk then your best option is Cozumel Palace (CP). At a normal walking pace it is about 15 minutes to walk to town.
Cozumel Hotel and Resort: It is probably a little further than 1/4 of a mile out past CP. You can walk it but you would typically take a cab.
Intercontinental: You would need a cab to go back and forth.
Quality: I will define quality as up market, amenities, resturants, beach, etc
Intercontinental: this would be a 8 to 9 on a 10 point scale. They have a great spa onsite, an excellent beach, very good resturants, rooms are very nice.
Cozumel Palace: probably rate this as a 7 - 8 just because they don't have a beach where you can walk directly into the water. Otherwise it would be very close to Intercontinental
Cozumel Hotel and Resort: would rate this as 6 because of no real beach, resturants are just OK, rooms are Ok.
All inclusive: You need to decide on whether or not you want an all inclusive or not. One of the potentialdraw backs for some staying at the Cozumel Palace is that it is an all inclusive. Cozumel really has some very good resturants that you should try to take advantage of while you are there. You don't have to always eat at an all-inclusive but my experience has been since you already paid for it you make a point of eating there given you paid for it. While the other two hotels can be booked as all inclusive or not.
Cost: We own a condo in Cozumel and usually stay there so I have not checked recently on prices. I would guess you will have quotes that would show the costs to be in this order: Intercontinental and Cozumel Palace comparable (with CP being a little less) unless they are running a special. Cozumel Hotel should be considerably less.
Dive operators: to my knowledge, unless something has just changed recently, all dive operators can pick up at the dock. It is not quite as easy to get to the Cozumel Hotel dock as the hotel is on the inland side of the street and to get to the dock you can either go through the tunnel or walk across the street. No big deal but just not as convenient.
If you have any specific questions don't hestitate to contact me. Be glad to help if I can.
Merganser1
Katy, Texas