Chose this cruise for dates, itinerary and value. Regal Princess is beautifully appointed. Mini suite was large and comfortable, but noisy. Very international passenger list made for cross cultural opportunities. Sold out cruise resulted in some very crowded breakfasts. Stage shows were disappointing, other musical entertainment was excellent. Although I missed having a true Piano Bar. Art lectures and shore lectures were interesting. Food other than specialty was disappointingly average. Even specialty seemed to have same menu every night. Overall good cruise with excellent itinerary. 2 days in St Petersburg is a must and even that was barely long enough.
If you want to see Berlin I recommend joining the cruise there and going in a day or 2 early. It was 3 hrs. travel by train and bus to get to downtown Berlin. We chose the Berlin on Own excursion and then went to the Pergamum and Neues Museums. Fabulous but made a 12hr+ excursion.