The ports were all worthwhile, each had something memorable for us and it was our first time in most of the Cities: Copenhagen, Oslo, Bremen/Bremerhaven, Amsterdam, Brussels/Bruges (Zeebrugge),Paris/Normandy (Le Havre), and ending in Southhampton. The one-way route worked for us, or at least we were able to make it work.
Ok so we have only taken 2 other recent cruises, on Celebrity, so take this review for what that's worth.
We'll start with the food, since we had a great experience with Celebrity; the food on Vison of the Seas was basically like one of the USA chain resteraunt $12 dinner buffets: boring, repetitive, generally not good quality. Also they often had only one side open which created long lines at times. The main restaraunt had exactly the same food as the buffet, I mean exactly the same, and the room service was limited to hog dogs and the like. The last night of the cruise the buffet was actually better, they pulled out a few new dishes and some were actually decent. If they had made that much effort every night it would have been so-so.