The West end beach is awesome! We went to Bananarama which had great food and had coconut trees over a wooden deck. It was wonderful. We got the coconut shrimp which had 8 SUPER sized yummy shrimp for $15.
Unless you are doing a Jungle tour, I suggest staying on the boat. This town needs a lot of work and is very poor. We walked into the city for 30 minutes and then went back on the boat. We were very disappointed.
I have been to Cozumel many times and it is always awesome. One of our fav restaurants is Jeanie's. It is right across from the MEGA store. It is on the beach, so you can sit and enjoy your food and drink with a great view!