I suggest that the QM2 is too retro, with its restaurants, cigars, bars & deck chairs straight out of the 1950s. There isn't much to do on the typical 5-day crossing, except sit at the pools or walk the deck (3 times around is a mile). The highlight of the day for many of us was the Trivial Pursuit contest! The food in the main dining room is uneven; some good meals, some pretty bad. The buffet is OK but nothing outstanding. The drinks & Wi-Fi are expensive.
We departed Hamburg (a fascinating, smallish city) & stopped at Southampton. There are some interesting day trips from that port arranged through Cunard, including Stonehenge and Salisbury; for a change, the excursions are reasonably priced. My rating is based on the overall experience, including the sleeping room, common rooms, and crew service (almost entirely terrific), and reflects my experience with other (frankly inferior) ships.
Small but comfortable cabin. Nicely appointed with sufficient closet & cabinet space. I didn't spend much time in the cabin so I'd say it was certainly more than adequate.
The Brooklyn port location is really remote & inconvenient for most people.