Very specifically, I would recommend the Radisson Paul Gauguin to friends. It cruises French Polynesia. If you catch it when it is "on special" and with "free air", it's not really overly expensive when you consider that most everything is included,except for alcohol at some times and places, and shore excursions. EVERYONE who has taken it has liked it, except for one person who does not like tropical cruises (Duh?).
I have no recommendation for enemies. On other ships/lines we've had and heard both good and bad experiences. For enemies, I'd have to purposely mismatch their personalities and tastes to the ship, as one man's Heaven is another man's hell. So I would send the "party animals" to the Seven Seas Voyager and quiet types who like space and privacy to one of Carnival's mega ships!