I have been to Europe and the caribbean. In the caribbean everything is very casual. U can wear shorts and flip flops everywhere. In europe it's a little more business casual. on the ship u can wear shorts and flip flops; but alot of the shore excursions tell you what men and woman should wear. My wife and I went to a greek monestary and they required women to cover up; i.e. no shorts or sleeveless shirts. I wore casual slacks on most shore excursions. On royal caribbean ships in Europe they allow smoking. Europeans smoke a lot more than us; so Royal allows it. On our ship there were mostly people from england, ireland, and other countries. There were about 26% americans onboard. We are going to Europe this summer becuase its worth it to visit all the nice ports of call. The shore excursions cost a little more in Europe. This is because it's more expensive for RCI to operate in Europe; the docking, restocking, fueling, is more expensive. But I will take a Europe cruise over the Caribbean anytime and all time.
Freedom of the Seas Dec 11
Allure of the Seas: Jan 11
Voyager of the Seas: May 09
Splendour of the Seas: May 07
Explorer of the Seas: Jan 04
Majesty of the Seas Jan 99
The ports are the biggest differences. NO comparison for sightseeing and interest. If you want beaches and sun, go to the carrbean.
But as to your other questions, we have taken two 12 day cruises- one a western med with Carnival and one eastern with NCL. Both had the same activities, food menus, trivia, quest, etc etc... Would totally expect RCCl to be the same. As for Europeans onboard, we found that Americans were to vast majority, with a lot of people from England too. I think the annoucements were in English and Spanish but that may change on each voyage depending on the mix of passengers. I really think Europeans go for the European cruise lines to avoid the "noisy" americans...