Yes, Galaxy is a Century class ship but she's quite different inside. She improves on Century in having better access to the dining room via a 3 deck aft foyer, adds a quiet aft pool (usually quiet). Her Tastings is different, more private feeling, her Cova is in a separate area (some call it the poodle lounge). Her observation lounge is improved, it is on 2 levels and has dramatic, tall windows with exceptional views.
Her decor is quite different, not only colors, but the furniture is different, different foyer, dining room (nothing like the Century's), etc. I think the differences are interesting and I like the Galaxy better than the Century and Galaxy most of Celebrity's fleet. Staterooms are the same size.
Dancing, Galaxy has the same 3 areas to dance, Rendezvous, Savoy Lounge (Galaxy's Crystal, somewhat similar to Century's Crystal but jazzier), and the Observation lounge/disco area. Galaxy's Rendezvous has a larger dance floor than Century's. I just hope you get the ballroom dancing on the Galaxy, I sailed the Constellation on the Southern Caribbean route and was very annoyed that there was little ballroom dancing aboard that ship (had plenty of it on Galaxy and Century in Alaska and Europe, respectively)
Galaxy should be fine for you if you enjoyed Century.
