This is our sixth time with Celebrity, but the first time on the Constellation. Embarkation was a breeze, took less than 20 minutes from leaving the hotel room to boarding the ship. If you are departing from Amsterdam I would recommend the Movenpick Hotel, it's right next to the cruise terminal. The ship looks a little dated, but it was clean and overall pretty good. The food and service in the Ocean Liner restaurant was very good, the Tuscan Grill was so-so. We were on Select Dining option and had no problem getting seated whenever we wanted, food in the main dining room was good, but nothing special. Breakfast buffet was good, with lots of fresh fruit and stations for poached eggs and omelets. Lunch and dinner buffets also had good choices, fresh sushi in the evenings, and a good selection of choices, (pasta bar, curries, Asian stir fry's etc.)
The ports of call were ok, with St Petersburg being the highlight. We booked a tour through Alla Tours, and were delighted with the itinery, guide and driver. We had the Classic berevage package and made good use of it in the Martini Bar and Reflections Lounge. Bar staff were always ready to refill the glass, and not having to sign for drinks everytime was a bonus.
In summary the cruise was as good as we expected, but was not outstanding. We'll cruise on Celebrity again, but maybe not on the Constellation.