Went on Liberty of the Seas on December 25, 2013 with my husband, daughter (16) and son (19). My daughter had a great time, loved being in the teen club and meeting other kids. My son was too old for the teen groups and not old enough for the over 21 activities, so there wasn't too much for him to do. My husband and I were shocked by the terrible service. The staff stood around talking to each other and seemed peeved when you asked for something. Even the staff at the main customer service desk were awful. The exception was our stateroom attendant, who was lovely and very accommodating.
The fitness center is large but very crowded. They have no system for signing up for exercise machines. You just have to wait around, loiter, and try to get on one. Makes for an unpleasant experience when several people are waiting to pounce.
There was a constant sense of being "nickel and dimed" -- the "free" tea was lousy no-name tea. If you wanted decent tea you had to pay extra in the cafe for it. Free ice cream was available for a limited time, so if you wanted ice cream in the evening you had to pay for it at Ben and Jerry's.