I board Oasis next weekend for the third time on this class of ship. It'll likely be the last time for a while since I like the older ships in the RCI fleet and the Caribbean itineraries the Oasis and Allure have to do are tiresome. But as others have said, I simply find that RCI suits me and they get the lion's share of my business. To each his own. And to be honest I think RCI has the best loyalty perks. Again, just my opinion. Nothing against Carnival, which I happen to like, but that line has become a 'drive to only' option for me.
Pete - I agree with you about the Solstice-class. Love those ships!