I’ve done several of these two night cruises to Hamburg; they are good value if you are travelling in grills, plat or diamond status because you can get on early, enjoy lunch on embarkation, and on day two afternoon tea in the grills lounge which is much more relaxed than the chaos of Queens room.
It’s important to know that because people are on board for two days, the bars are very busy, and particular things like lunch and the Queens room afternoon tea you might find more crowds than it normally the case on a transatlantic.
Order room service on day two because you won’t be able to do so the morning you are cruising up the Elbe, and get up early that day as the sunrise and watching people in the houses alongside the river enjoying that early morning coffee as the ship passes by are quite something .
It’s a great way to get a feeling for the ship, the style of service he might expect to board Cunard as well as checking out things like the spa and the various venues on board which is difficult to get a handle on from purely looking at the website.
A little tip; if you’re coming off in Hamburg during the summertime, walk the kilometre to the ferry stop and ride that into the centre of town with your hand baggage, enjoy a beer at the “Alex“ pub/restaurant overlooking the harbour, and book ahead for the miniature Wonderland which is essential but does get booked out early.
Fly back on British Airways in Club Europe (use points) which includes access to a comfortable lounge at Hamburg Airport which has very good runway views. Also consider a tour of Bergen Belsen if you are there for a few nights.