Royal Caribbean does an excellent job of getting passengers on and off the ship, including at ports of call. There are several security checkpoints each time, but everything ran smoothly, with no real waits in line. Just be prepared for airport-level security, and don't forget your Sea Pass card and photo ID, especially in Nassau.
We had a stateroom with a balcony overlooking Central Park. In retrospect we should have chosen an ocean-view cabin. While a park on a ship is a novelty, I can see trees anytime in Ohio; I can't see an ocean or tropical islands ! The stateroom was very nice, not as small as I thought it would be (though the bathroom is tiny!). I thought there was plenty of closet space too. Soundproofing is excellent. Even though the Oasis is huge, you WILL feel the ship moving in the water; staterooms on lower decks have less movement. The movement was never enough to be a problem, though, even with ten-foot swells.
Note to first-time cruisers: In the stateroom there is a small step up to the bathroom, which can take some getting used to. For the first couple of nights, I put a white washcloth on the floor in front of the step, to remind me it was there.
Adequate closet space, good sized balcony, quiet location (be sure to close the balcony door tightly, this helps with the soundproofing). Mid-ship location, but still a long walk due to size of ship. We overlooked Central Park but in future will book ocean views; the park view is nice but not all that exciting, like an atrium view in any land hotel.