Back today from a 2 week cruise in the Caribbean. Went with Tui on the Marella ship.
I can see why some people call it Butlins at Sea, some on the people on there seemed to spend the whole time on the smoking deck getting pissed and wouldn't look out of place as extras on Shameless.
That said, one of the best experiences I've ever had, 95% of the people were great, seeing and exploring 11 different islands in 14 days was tiring but well worth it, some never even left the ship
Went quad biking around St Maarten, snorkeling above shipwrecks and with Turtles in Barbados, driving through the rainforest and swimming in natural pools in Dominica, Kayaking through caves in St Vincent.
Other highlights included an excursion called the Rhum Runner in Grenada, basically a 3 hour boat/beach trip, strongest rum I've ever known, many barely made it back to the ship also played beach cricket with some locals and drinking with the Barmy Army in Antigua. I know cruises can get a bad reputation and with some of the clientele I can see why sometimes, but if you do them right it can be a wonderful experience.