These are comments I posted some time ago, but I think they are relevant to this subject.
My wife and I have recently returned from a 14 day Christmas cruise aboard the QM2. We were in Queens Grill accomodations and although the ship itself is a worthy addition to the Cunard heritage, the total experience does not begin to measure up to any of our cruises on Crystal.
Our room was very nice and was somewhat roomier than a comparable PS on a Crystal ship. This was accomplished by only having one sink in the bathroom, a combination tub/shower and no bidet. The extra room gave a few more square feet in the cabin and an extra closet separate from the walk-in closet.
The food was not up to Crystal standards and the service was efficient but very mechanical and hurried. Our waiter in the Queens Grill (who should have been one of the more experienced waiters on board) had never been on a cruise ship before, whereas Crystal requires at least two years experience on another cruise line before they will consider you for employment.
The public rooms were well fitted out, but any of the Crystal ships have a superior layout. For example, the QM2 has a Winter Garden which is similar to Crystal's quiet and peaceful Palm Court Room. However, the Winter Garden sits astride a very busy part of the ship and people are constantly streaming through it. Additionally, the QM2 has many lounges and bar areas, but nothing close to the intimacy of the Avenue Bar or even the Vista Lounge. The closest was the Commodore Club, but the windows had to be covered at night so the reflection would not disturb the bridge.
Finally, the QM2 is so large that tendering is the norm at most ports. We typically had to go to the Queens Room, get a number and wait 30 to 45 minutes to get a tender into the port. I suppose with 2600 people on board this is inevitable.
We plan on sailing exclusively with Crystal in the future; it is simply the very best Cruise Line in the market today.