We went on the Carnival Liberty from Barbados back in December 2015.The boarding experience was very quick and easy, mainly due to the fact only 150 people boarded in Bridgetown, the rest of the people had boarded in San Juan. Puerto Rico.
The Carnival Liberty was a bit run down in parts but very good in most parts. When we went on Royal Carrabeans Independence of the Seas 2 years ago we used to look forward to our meals (especially) the evening meals as the food was excellent, but not so on the Liberty, just at best average.
We tried the entertainment which was ok but seemed to cater for the American sense of humor, yes they say Carnival are party ships, but the music was just too loud at times.