I will never go on a Carnival Cruise again! We cruised on the Sensation as a repeat Carnival guest. We have been on several cruises and this was the worst experience I have ever had.
The main problem was with the Cabin. Primarily the fact that our air conditioning unit in all 4 cabins we had reserved was on the blink. After several complaints, they finally brought fans into the cabins which blew around hot air. Even though they told us that a technician had come by to check the room temp and it was only 74 degrees, we never saw the technician nor the thermometer and I know that there was no way that I would be sweating if the temp. was only 74 degrees. My sister slept with a cold wash rag on her head at night.
Also, just about every night our circuits in the room went out to our plug ins, which made us late to dinner one night. The only thing they offered on board was a voucher for a few free photos.