As I stated on my tips for Grand Caymand I have not been on the Western cruise but I have been to Cozumel too many times to count. Cozumel is a really cute little town. If you like to stroll around and shop it is a good place. The locals are very nice and they will bargain with you but they are not overly pushy. You can take a cab to the town center and just walk all over, it is very safe and we have never had any problems. There are lots of cute restaurants and bars where you can grab a drink or lunch. Pizza Rolandi is right on the main drag. It has the best pizza and pasta I've ever eaten! They also have great sangria and it is a really cute restaurant. Just ask the cab driver to take you there. I have been to the Mayan ruins on Cozumel and I would not recommend them. The snorkeling is great in Chakanaub (sp?) In addition to fish they have sunken statutes and stuff. You can also see iguanas and such. I personally would not go to Tulum or Xcarat. Once again, I have been to both and they are great but it would be a really long trip in the time frame and I think it would be exhausting. Cozumel is really quite nice and I would take advantage of time there. The beaches tend to be a bit rockey but the water is beautiful and there are lots of fish. If you happed to be a diver go for it! There are tons of little dive shops around, I would recommend Blue Bubble.