My main concern before the cruise was the age of the Century (now 15 years), having chosen previous cruises for the newness of the ships. Our concerns were unfound and we thought the Century was very elegant, filled with interesting artwork, well maintained and up-to-date, with many nooks and crannies around the ship. It is a very accessible size and it never felt crowded, even in the buffet area. The only place the age of the ship was evident was in the occasional window with condensation trapped between the panes of glass, making the window opaque. But I can recommend the ship with confidence, as long as someone isn't interested in the newest innovations.
The Concierge-level cabin (standard size) was cozy, but had plenty of storage and a very well designed bathroom, especially the shower. It seems that the designers went for more storage and bathroom space at the slight expense of cabin living space (my wife and I would bump into each other at the narrowest point between the bed and the fridge). The balcony was just fine and the sliding door seemed brand-new and very sturdy.
We liked the food in the main dining room, which was probably a notch or two nicer than we've experienced before (with the exception of Queens Grill on Queen Mary 2, which is a whole different category). The buffet restaurant was very classy, with many different choices, including a rather nice poached egg station for breakfast at the very aft area, with many clever variations of poached eggs, served in white ramekins. The Spa Cafe was also a nice treat.
The only problem we had was with Celebrity Select dining, which the staff on this ship is clearly still trying to figure out. As we boarded, we could see the final touches being made on the Select dining area, which was the upper level, starboard side, which involved cutting many larger tables into numerous tables for two. We actually only had problems on the nights when we had failed to make a reservation. On other lines, we became accustomed to simply showing up whenever we wanted as part of their "anytime dining" concept, with few problems. It turns out that Select dining on Celebrity works best when you make a reservation ahead of time, in which case, we were seated right away at a table for two. Celebrity just needs to reinforce that reservations are essential to avoid frustration.
The one major flaw with the Century may not matter to most guests, but as with some other ships, it's a shame that it lacks a promenade deck that goes all the way around. The usual side sections of the deck 6 promenade are gorgeous, with teak flooring and much greater width than usual -- very nice for an evening stroll after dinner or a show. And I can deal with the aft section that wraps around the ship, albeit requiring a flight of stairs up to deck 7. But when you try to go forward, you hit a dead end, "crew only" zone, with no apparent way to get around to the other side. Similarly, up on the pool level, there weren't any decks that allowed you to walk all the way around the ship outdoors without going up and down some stairs. I guess I'm a traditionalist who thinks that all ships should have proper promenade decks that wrap all the way around (QM2 was the best!).
Overall, we had a great cruise and we'd consider Celebrity again.