Our first cruise on the Royal Caribbeans Mariner of the Seas was absolutely awesome - and has set a high level of expectation for our next cruise. In spite of the huge number of passengers to deal with we found all the staff extremely helpful, willing to assist and very courteous. The ship itself was fantastic.
Obviously with the large number of people on-board (and trying to embark/disembark) there will be the usual delays (so get over it or get used to it!).
In spite of all this, we found that the organization was very well done under the circumstances. We went on a different port excursion every day and found it no issue on finding out what/where we had to be and directions to get to and from. The excursions themselves were well organized and we were truly looked after. Our guides were very conversant and all of us enjoyed the time ashore. Hint: Book excursions before you get on board - or prepare to wait in a very long line.
We had the "Superior Ocean view Stateroom" which, while smallish (I suggest you get on well with your kids. If you dislike them then book them their own room!) was more than adequate for a family of four (including two kids 13 and 15) who had no plans to spend all their time on board in the room.Well laid out, very clean and tidy, and no complaints on the set up. The balcony was a bonus as the other half likes her peace and quite away from the bustle of the world.