I only went last year, but feel I picked well based on what many vet-friends had told me.
I went with a balcony room on level 10. LOVE the balcony and wouldn't give it up. True, I spent most of my time out of the room, but I did spend some time in there. The JC-TV rocks when you are slowly getting moving after a few hours of being crashed-out in the wee-hours. As someone stated above, I enjoyed my private room with my sweet wife and had a lot of private adult fun in there...hehe....
Also, great to be able to have some downtime on the balcony, chill, read a book, enjoy a cocktail, etc. I didn't chill very much or for very long, but I did it some and was glad I could. But then again, I could see NOT having it, too...back in my college days I would have taken a no balcony room and been perfectly happy - plenty of places to enjoy outside in relative private on the top deck...it's pretty huge. But now I have the cash and it's a lovely perk, so....balcony room it is!
I liked level 10 because it was sandwiched between the top deck and the level with the zebra lounge and theater below. So quick and easy access to either of the main music areas. The room we were in was pretty close to the stairs/elevator, so that was convenient. Also, we were closer to the front of the boat, which is quieter and has less vibration action than the rear where the engines are located.
Anyhoo...that's my two cents from my one experience on board last year.
Can't f'n WAIT!!!!!!!!!!!!!!!!!!