My first (excellent) Celebrity experince was a 10 day on Horizon. I have also done the sister ship , Zenith as well as three other Celebrity cruises. Dining room food and service is excellent, steward service is as well. Service and attention around the ship are all of Celebritiy's high standards. No soaring lobbies and no 22 bars and clubs on Horizon. 5 or six very nice entertainment venues, a nice compact little shopping area and a nice (small) Casino. Most public spaces do double duty by day and night.
Pool area has some nice shaded space on the lower level and plenty of "nearby space on the deck above. A nice series of quiet decks at the stern make for more restfull reading and sunning if that is what you like.
A very nice example of Celebrity . Hope it stays this way through Horizons transfer later this Fall to another cruise line owned by RCCL.