We're also searching for a cruise this Fall. Looking at an 8 day on the Carnival Conquest that includes St. Kitts, St. Thomas, San Juan & Grand Turk. It would be a different itinerary for us!
We might in the minority, but we really enjoy Carnival. We're also a young couple without kids, but we aren't huge partiers or drinkers either. We've always had a great experience with food, entertainment, guest service, etc. No complaints here
We also considered the Oasis & the Allure, but after doing a video tour on Youtube, we just aren't sure we'd enjoy ships that size! I know there is tons to do, but I like the feeling of actually being on a ship, being able to see the ocean, etc. Those megaships are beautiful, but almost too hotel-like for us.
We are considering an NCL ship as well, but for some reason, I just can't get excited about Norwegian. No idea why!