Kuki, I would echo the previous poster's comments. What aspect of Cunard are you interested in because the QM2 does vary slightly from her smaller sisters the new QE and the QV.
On the QM2 except for embarkation day afternoon tea is served by white-gloved waiters in the ballroom and it's very popular. She has the only Planetarium at sea and all 3 ships have excellent libraries.
Are you interested in a transatlantic or a cruise-type voyage? That would dictate which ship you choose since the QV and QE do only a few crossings per year.
Sun Princess (2 times), Mississippi Queen, Dawn Princess, Coral Princess (2 times), Regal Princess, Grand Princess (2 times), Diamond Princess, Maasdam, QM2 (15 times)