This was our first cruise on Royal Caribbean and the first cruise for my daughter and son-in-law (late 20's). It was the fourth for my husband and I (very late 50's).
STATEROOM: Our balcony stateroom was lovely. The room had plenty of storage for us and had a small couch. I think it was the best designed stateroom we've had to date. It felt quite spacious considering we were on a ship. (It helps when you keep everything tidy.) The balcony was totally covered, which we like. The TV was old but the ship is getting flat screens when it's being refurbished in the spring. Karen, our stateroom attendant was wonderful. She kept our room clean and made us three towel animals. Although I know it costs more, I think you really would miss out if you didn't at least have a window view of the ocean.
LIBRARY: We were located right next to the very comfortable library. It had leather couches and was well lit and relatively quiet. Oh, and it had books. I lean towards the area where guests swap books but, with the advent of Kindle, there weren't all that many to choose from.