Our vote goes to Mr Sanchos Beach...well maintained, top noch facilities, many activities to keep you from being lazy in the sun ...we checked the cozumelwatersports beach factory and there is a whole lot of activities to chose from. We were there in January and return in August (yes, we are cruise addicts haha).
Sanchos is all you can eat, Nachi is just a meal (I hate somebody serving me a set meal on vacation...I have this on business meetings )
There is no nicer beach than Sanchos, Nachi is a cruise spoiled and crowded little beach, Paradise is MUCH too expensive...just check their menu when going...just for using the beach toys is a $10 extra!!!
I have 10 days or less to decide which beach to go to. Was just going to take a cab to one, but mat actually have to book ahead like for Nacho Beach. I just want something all I can drink and eat, and then cab back down to the stores and back on the ship before it leaves