We travelled on the Oasis of the Seas in March 2011 as a party of 13 family members aging from 70 to 6.
The overall experience was very positive - there is lots to like about the Oasis. On balance, however, we felt that it was perhaps a little "too big" compared to the Liberty of the Seas and others of that class. On Liberty, there were almost as many activities but it felt a little more manageable.
We stayed at the Rodeway Inn in Ft. Lauderdale the night before. Nothing fancy but clean. The free shuttle on the day of departure was slow and we had to wait longer than we expected. I suggest you pay $2 per person for the "early" shuttle.
Embarkation was very organized, quick and efficient. Getting back on the ship while in ports was apparently very slow near departure time, which we usually avoided. It was also very annoying that security to get back aboard forced us to give us half bottles of water every time we got back on!
We stayed on Deck 11 which was one of the best decks. I would say Deck 10, 11 or 12 are the best locations if you want to visit the whole ship on a regular basis. The cabin was fine - small but very well designed. There were two plugs under the vanity which was fine for us (unlike other reviewers). There is another one by the bed.
The pool deck was the only area where you really felt like you were on a ship with 6,000 passengers. It was very hard to get a lounge chair on At Sea days. They need to be more aggressive on removing towels from chairs after 30 minutes as they promise. Other areas are not too crowded, but it is quite hard to find and meet up with people. I would recommend walkie-talkies for a large group.
The food in the regular dining rooms was fine. We did not try any specialty dining (other than Johnny Rickets for breakfast which we would not recommend). The Windjammer is small for the number of passengers, but there are so many other dining choices that we rarely ate there. The Solarium serves healthier food (for example, you have to ask for butter at breakfast) - this is where we ate breakfast every day, and often lunch as well. The Park Cafe was great, but busty at peak times. The cupcakes were very poorly recovered in our group (especially the icing). Donuts were OK, but nothing to write home about. You can get free frozen yogurt in the Wipe Out Cafe or the pool deck any time. We enjoyed the almost empty Viking Bar on Deck 17 a few times. The drinks are expensive but the view and ambience great.
Hard to believe that they allow smoking anywhere in this day and age. Even though the casino was divided in half into smoking and non-smoking, the smoke is very noticeable all over.
All of the evening entertainment was very good. The Aqua Show was excellent, as was Hairspray and the Come Fly with Me. We skipped the Headliner - a crooner from Las Vegas. The comedy show was so-so - one comedian was very funny, but the others were not.
The sports facilities are great for the active cruisers. The Flowrider was a big hit, but I strongly recommend renting it for a private lesson (8 people needed for one whole machine). That way, you get a bunch of long turns and can have fun with the instructors too. Mini-golf (but the plastic balls were too light and course could have been more exciting), zip-lining (very tame), climbing wall, sports court, the list goes on and on. The skating was very popular - more time for free skating would be great. The gym is state-of-the-art. The running/walking track on the 5th deck is a big improvement over other ships. Great choices for active people.
The wireless internet is expensive and slow (not as bad a dial up, but close). But worst of all, it was often unavailable completely which was very very frustrating.
The ports on the eastern Caribbean are OK, but fairly bland. The ship leaves Nassau at 2pm, so there is not really time to do anything serious. We did not even get off in St. Thomas - enjoyed the deserted pool deck area. We did go jet skiing in St. Maarten which was fun. But there were six ships in port so it was very busy. A stop at Labadee would have been great.
For disembarkation, we were in no rush to get to the airport so chose the "regular" system of leaving your bags out the night before and then waiting in the Opus restaurant at the appointed time. It seemed to be working well until we got stuck in an endless line-up to file off the ship. I would strongly recommend the self-service walk off program (take your own bags), even if you don't need to get off before 7:30am (the last time for walk off).
Overall, we had a great time, but there were a few annoying things that would make us think twice about choosing this ship over the next size down.