We took a 5 day sail on Mariner for the - you guessed it - grandkids! Overall it was a great experience and exceeded my expectations (which were not very high) Fortunately we (the grandparents) were "Diamond" and really glad about our perks - esp. the coffee available and the peace and quiet in the sky lounge. We managed to get a table assigned to us after sailing as we had signed up for "my time" and that didn't work with our 8 and 12 year olds. The dining room food ranged from rarely inedible (shrimp risotto) to not bad on most nights. I did miss the every day choices Celebrity has on their nightly menu.Choices in lido cafe very good, esp. Indian dishes.
Overall the kids loved it and could easily access the slides and other features. It is unlikely I will sail RCL again unless with children. It was quite crowded and actives at some of the venues did not fit! Trivia in Schooner bar way too crowded. But RCL is great as a family destination.
One more gripe - we received several prompts from RCL to board at our assigned time - we thought we ad an early time 1:00 pm and arrived about 12;45. We could hardly find a parking space and the ship was already a hive of activity. I think if they are going to tell people an assigned time, they should make some effort to proceed with that expectation.