DISASTER cabins on the Horizon/Zenith:
Caribbean Deck AFT of ship. Approximately cabins numbers from 6129 to 6175.
The Caribbean Deck in underneath the kitchen galley and all night long you here machinery running and carts rolling around. You will also hear the ship's engines a vibrations from that as well.
I learned my lesson the hard way and I will never make that mistake again. I now only book my cabins sandwiched between other rooms on the upper and middle area of the ship.
Although I have noticed the newer ships do not have any rooms below the kitchen galley.