We were on the Solstice followed by the Discovery. I know, one is older and one new but it was more than that. We were just a little bored on Celebrity with no daytime activities to keep us occupied. I must say, I think we really missed the Medallion and the app on Celebrity and the ability to get a snack in the middle of the day without going to the buffet or being in our cabin and paying a room service charge.
Also, I think that Princess handled the embarkation and immigration processes better. But, I am well aware that those things can be handled differently week by week depending on circumstances.