We just returned from a great trip on Oasis of the Seas, western Caribbean itinerary. We traveled with our three kids, ages 15, 12 and 10 as well as another family of four. This is our 6th cruise. I was very apprehensive about the size of the ship and the crowds, but I was very pleasantly surprised that crowds did not seem any bigger than what I'd experienced on smaller cruise ships in the 2000 - 3000 passenger range. This was true with a few exceptions I'll note below.
Precruise we stayed at the Marriott Springhill Suites in Fort Lauderdale. I posted a review and pictures on Trip Advisor if you're interested. Definitely recommend this property for a precruise stay.
We were in balcony cabin 7140 on the port side near the front of the ship. Our children were in an inside cabin across the hall. We were happy with this deck as it was close to the promenade and Central Park. It was, however, eight decks below the pool deck.