So I will place a disclaimer right away. I have never been attracted to the idea of cruising - and would not have booked this trip - except my parents, and some siblings and extended family were going. All of them have cruised before. The overall group opinion was that it was "just ok."
From a first time cruiser opinion, there were some annoyances that I could have done without:
LINES! There are LINES everywhere. The line to embark the board actually went fairly smooth. No complaints over that process. However - from that point on, the lines were just ridiculous. There were lines to get food every time (on the Lido Deck / The Gathering). The first day was a "fun at sea day" and, well, truth be told, little fun to be had. There was a line for breakfast, a line to get a seat to eat the breakfast, a line to get drinks, a line actually formed waiting for a beach chair by the pool. The lines continued - a line to get the elevator (sometimes up to 10 minutes), a line to get off the ship at the ports, a line to get back on (We did see other ships that had more than one or two doors open, not sure why Carnival only had one or two at each port)