If you have never cruised before, you will be amazed when you see the ship. It is absolutely huge. Embarkation was really the only thing that sucked about our whole cruise - it took FOREVER and you have to stand in line for 2-3 hours. Once we got on the ship though, everything was great.
I had read some of the reviews of the "Sensation" before we left and I supposed maybe if you had cruised a bunch of times before, maybe the Sensation would be a disappointment but we thought it was awesome. There is a "retro" motif in the main lobby and throughout most of the ship. There are about 6 bars throughout the ship - you really have to enjoy drinking to go on a cruise. We never even got near the pools, as they are either crowded with children or closed because the ship is swaying to much to use them. We didn't use the hot tubs either - again, usually small children in there. I think there should be some "adults only" pools and hot tubs onboard the ships.
Usually you don't have to wait to get drinks - the lines at the bar move fast and there are numerous drink waiters roaming around at your beck and call. The frozen drinks are really good. The only problem with the mixed drinks or the "drink of the day" is that they are REALLY strong - lots of alcohol. At least you get what you're paying for, I guess. It was really too windy for most of our cruise to use the sports deck, where they have a jogging track, volleyball, and shuffleboard. We DID play ping pong though, and that was fun. Try doing it on a really windy day though! Whew!! I also didn't get to use the gym but it looked pretty cool.