Absolutely fantastic.
I have cruised with Royal Caribbean, Costa Crociere, Carnival, Holland America, Princess, Disney and Cunard in my lifetime, our sailing aboard Queen Mary 2 was exceptional. The ship is something special on her own, but when you consider the amazing attentiveness of the crew, from the Captain all the way down to the stateroom steward she becomes a bucket list experience. The crew to guest ratio is around 2:1 and you can tell as there is always a friendly face ready and willing to bring a drink or lend a hand. Her passenger capacity of around 2500 or so is wonderful on such a large ship (a little over 1100' long) shows in the Royal Theater were never jam packed and the Brittania Dining room always had tables available. Queen Mary 2 was fully booked on our trip but never once felt crowded.
We brought our 14 month old with us which worked out great. Again, the staff and crew couldn't have been nicer and more welcoming to her, she had her fruit plate and glass of milk served at dinner before we had all taken a seat, and we learned how to play and say, "peek-a-boo" in our server Oding's native Indonesian language.
Stunning beaches, we spent the day on the beach south of the cruise ship pier in Bridgetown. I can't remember the name, but it was stunning.