We are a family of 3 and this was a our second cruise ever so we only have one other cruise to compare to.
The Oasis of the Sea was great in terms of size cleanliness and entertainment options. However, the things that stood out for us (in a negative way) was the service and food.
Service - The crew members that we came across seemed like they were in "drone mode". Once you engage them in a conversation they would smile but once the conversation was over it seemed like they defaulted back to a straight face. This goes from our room attendant to the waiters and waitresses. The only exceptions were the crew at the Customer Service desk or stores. (This is in comparison to the crew on the Norwegian Epic we took 2 years back. Where everyone seemed to be on a good day. Norwegian's crew was friendly, engaging, interested, and part time comedian for the most part). Some examples of RCL crew...
Spacious comfortable bed but the age of the ship is starting to show.
Port of call was large make sure you know which gate you are going to ahead of time if you make the mistake of walking to the wrong gate it is quite a stroll to the next.