Have previously been on the Queen Mary 2, Queen Victoria, Queen Elizabeth (twice) and Aurora.
One of my Queen Elizabeth cruises was in June 2014 with my husband. We went for 3 nights to Zeebrugge and had a fantastic time. Service and food no different to the longer cruises and a good mix of people.
Having enjoyed this short cruise I also went on Aurora in November 2014 with 2 friends for 2 nights to Zeebrugge. Although we thought the ship was dated and tired (it had a refit shortly afterwards), the service was very good as was the food. I was worried about what our fellow passengers would be like having spoken to a fellow passenger on the QE who had been on a P&O 2 night cruise and said it was like a booze cruise with lots of drunk and badly behaved people. We did not encounter this on our cruise.
Cabin ok but needs a refit. Very stable part of the ship but not great when lots of rowdy people walking past at 3am! Probably better if doing a short cruise to pay extra for a balcony or pick a cabin at the back or front to minimise the number of people walking past.