Except the Princess cruise ports are Princess Cays (private Island), Grand Cayman, Cozumel and Ochos Rios...and it's like half of the singles cruises do this itenerary. I've already been to those places twice, and they all really look alike after awhile.
The ports are only half the fun of a cruise. You really have to be careful with a singles cruise since so much is about the other singles on there. I personally like days at sea for singles cruises. You get more time for socializing around the pool and in the restaurants. When everyone is running around, it's hard to really get to know anyone.
I really do like Princess more than Carnival, but I'm never booking a cruise through an agency other than singlescruise.com again. I learned my lesson.