We were a party of 6 sailing out of Ft Lauderdale, to Southern Caribbean (Princess Cays, Curacao and Aruba). This was Christmas week, and the ship was full. Having cruised before with Royal Caribbean, Celebrity and also Princess, I must now say that Princess is now my favorite cruise line.
The service was great, the ship was big with lots going on - but not too big; the wait staff in the dining room was excellent, as was the food in the dining room. We were also very happy with our mini-suite, and the others in my party who were in inside cabins were pleased with their staterooms and felt they got a lot for the $. The ship did not feel crowded, even during this busy holiday time.
The shows were very good too - even my 22 year old daughter and her boyfriend like them (when last year, Celebrity catered to an older crowd). My only complaint is that the buffet food was not great, so we tried to eat most meals in the dining room.
Also I liked the Southern Caribbean itinerary - good to get plenty south for that warm Caribbean Sea and bright sunshine! Overall, I highly recommend Princess! Even my 19 year old has a blast - he met lots of people in his age group, thanks to the fact that they listed some meet and greets for 18+ 20 somethings (something Celebrity did not do last year). Compared to Royal Caribbean, Princess seems a lot more organized. Never a crowd - even the tendering process was a breeze - you got a number and relaxed at a table in the dining room until they called your group. In summary, go with Princess! This was our 7th cruise (in total) and definitely won't be our last!