Hello. We too are converts. After many cruises on Princess, we jumped ship to Celebrity, and then tried Oceania. Although we don't rule out Celebrity completely, we love O's smaller ships - fewer passengers, better service, delicious food. Our first O cruise was an oceanview on the Regatta - one of the R ships. Although the cabins are smaller than their larger sisters, we didn't mind it at all. No matter which category, you're never far from an outside deck. If entertainment is very important to you, I'd say it's not for you. Yes, there is usually some musical group in the bar area and generally daytime lectures or something like that. Regarding specialty restaurants, you're initially allotted a certain number of reservations in each restaurant based on your cabin category - which you can and should book prior to sailing. Once onboard, you can request additional reservations on an ad hoc basis.
Only you know if it's right for you. I'd recommend giving it a try. You might just love it like the rest of us! π