I have been on many carnival cruises, royal Caribbean cruises and Norweign cruises.
Pros of the Horizon: Italian specialty restaurant, food was spectacular. Dining staff was great, as was the whole crew staff. Good movie selections in cabin.
Cons: Low ceilings throughout ship. Atrium small with generic decor.
No windows and sitting area to just sit and gaze outside to look at ocean and just watch people walking by (very confining). No band and dance area in casino like they have on other carnival ships. Casino is small with poor layout. "Smart Elevator" system was terrible extremely long waiting time. Floors are very slick on lido deck. Lunch buffet horrendous. You will be eating a lot of Guy hamburgers, pizza and deli selections. I was never informed of the "Family Harbor" section of the ship so if you decide to go on this ship inquire about the Family Harbor. No pool in the serenity area. The entertainment was amateur hour. There are much better carnival ships just remember the newer the ship does not mean it's better.