The Constellation is one of Celebrity's smaller ships and my husband and I thoroughly enjoyed that. We easily navigated the ship from one end to the other.
We boarded the ship after spending a couple of hours in the Amsterdam airport (like a mall!) and the embarkation process was very smooth. Lots of people waiting in line but we were Elite status because of the number of cruises we've taken with Celebrity, so we didn't wait in line. We arrived around 11:30 and went to the buffet for lunch. The rooms weren't ready until around 1:00 p.m. We had a room with a balcony and I have to say, that, for this particular cruise, because the weather is cooler, a window room would have sufficed. We stood on the balcony for only very short periods.
We had late seating (8:30) and our waiter and assistant waiter were wonderful. Just the right amount of familiarity along with respect. We all hugged on the last day. We did tip both of them extra. The food was the best we've ever had on a Celebrity cruise. They have a new young (female!) chef who was very creative with her food choices. We didn't take advantage of any on-board activities as we were so tired after a day of touring in every port. Also, the time changes (1 hour ahead one day, 2 hours ahead another day, back to one hour ahead) made for a tiring time. However, we had a great time -- just catching up a few days after being back home.
The weather was cool but sunny most days, which we were grateful for. Wore layers as the sun made it warmer in the afternoons, but the temperature hovered around 70 degrees most days. Perfect for touring, but never used the swimming pool onboard. We had arranged for private tours (SPB) in every location, with the exception of Copenhagen, which we did on our own (hop on/hop off). We had a great experience with all the tour guides in every port. Most of them were graduate students in history or art. At the end of the cruise, we stayed for 2 extra nights in Amsterdam and had a blast.