We really like O and Regent. They are very similar experiences except almost everything is prepaid on Regent which makes it an amazingly easygoing experience. It’s hard to articulate the differences but it is somehow very nice to never show your card for drinks, the Butler stocks your stateroom with whatever you want, liquor, mixer, etc. It feels very luxurious and pampered. OTH you pay dearly for all that. Use the itinerary to chose which one to cruise.