I haven't been on a Royal Caribbean cruise for a while (5 years) and was disappointed with this service.
I wanted to "fly" and was super excited to go on the iFLY attraction - which was why we chose this ship. This allowed me to float in a wind tunnel, which was a great experience. However be advised that you need to book this attraction ASAP or else risk not being able to try it at all. You also can only go once per trip. So if you want to take your own photo, have someone stand outside (don't book all family/friends at the same timeslot).
The best part of the cruise was the activities and entertainment. The dancing excerise class was good (and packed), the music was good (they actually have hit music in Windjammer). The pool was fun when it was rocky (but can be crowded with people just standing around - so I like to do laps in the morning). The gym was decent sized, some classes (stretch, abs) were free but yoga and TRX would cost money. This ship doesn't have shower facilities by the gym so prepare to walk around in your swim suit if you want to go swimming/hot tub. This was kinda annoying because I had no where to put my room card.