We just got back from a great trip on the Spirit. This was our fifth cruise, though our first on Carnival. We have previously cruised on Princess, Celebrity, and Royal Caribbean.
The Spirit is a lovely ship, very clean, and easy to get around. Our obstructed ocean view cabin was large and well equipped, with very adequate storage, and the beds and pillows were very comfortable.
In my opinion, the food ranged from excellent (rack of lamb and prime rib) down to mostly very good, and one night, just good. I never had to send an entre back and request another, as I have on both celebrity and princess. We had table 125, for two, which we wanted, and it was perfect. Someone on this site had recommended it. The food in the buffet was average, but that has been my experience on all ships, and we seldom ate there.
To be honest, I had a slight bias against CArnival before this cruise and expected it to be slightly less than Princess or Celebrity. I am happy to report that it was not less, and that service was much better than on my last cruise on Celebrity Mercury. The only negatives were that there is no hand sanitizer as you find all over all other cruise lines, and there are the electric air blower type driers instead of paper towels in the public rest rooms. They did announce on their TV station that the hand sanitizers do not work again viruses, and that is why they do not have them.
We had totally smooth sailing except for the last day, which is to be expected when returning to San Diego and going against the current. Even that day was not too bad.
All in all, this is a ship and a cruise I would definitely recommend, and I would not hesitate to cruise on Carnival again.