I haven't been to the HR Cancun in years because there is not much of a beach there and the pool loses the sun midafternoon to the shadow of the Krystal next door.
Our taste runs to the Cancun Caribe. Diamond members get casitas on the beach and although the rooms are not very modern, they are serviceable and have great balconies looking out over the water. If the RC is closed, as it frequently is, you will get breakfast coupons and also evening drink coupons.
One warning - The restaurant at the Caribe is not much good for dinner, so if you do end up staying there, be prepared to go elsewhere.
Do a search on this board for more information.