We had the misfortune of being on the 6/11-6/19 Caribbean cruise on QM2.
From the beginning Cunard showed its ineptitude. Varying pieces of pre-boarding info gave conflicting requirements for passport. It was needed, it wasn't needed. Phone calls received the same yes/no responses. E-mail likewise yes/no. For this cruise, passports were not needed as it turned out, but conflicting answers from Cunard almost caused several members of our group to spend extra for rushed passports.
Boarding in NYC at 3pm went smoothly, greeted at end of gangway by crew members who smiled and pointed towards elevators, not very helpful, but not bad. Luggage was at rooms when we arrived. Briefly explored ship then decided to get a snack before sailing at 5. Eat before you get on, there was nothing open for dining until the restaurants opened up at 6pm. If you had late seating, as we did you could not eat until 8:30. Room service was available, but wait time was 2-2.5 hours.