We arrived in New Orleans the day before sailing to take in some sights. Just an FYI for those who don't know (like we didn't), restaurants will happily give your table away to the highest bidder, even after you have waited for an hour. This happened at Pat O'Brien. If you are hungry, don't go there.
Our overall experience on the Spirit was very positive. We have sailed with NCL numerous times and yes, have never been too impressed with their "free" dining options, but we do continue to sail on NCL because we LOVE the Freestyle concept. I have to say, the food has improved and the breakfast buffets were fantastic. Service in the main dining areas is very hit or miss. We were pleased with our cabin steward, but the rooms are TINY. We had an inside cabin on Deck 11. It looks like the room was made to accommodate 3, but they added a trundle under one of the beds so that it can sleep 4. If you planned on sleeping in the same bed as your spouse, that is not going to happen. Everyone had a single bed and there was no room to move anything. A family of 4 should definitely book a balcony cabin.
We decided to drive to New Orleans and instead of parking at the ship's lot, we chose to park at Machu Picchu. The lot is about 5 min. from the terminal, they provide a round trip shuttle and pick you up within a few minutes of calling them. The advantage is not having to wait for your car once you disembark, although I don't know if that's an issue. We were very happy with Machu Picchu Parking. Embarkation - I would not arrive between 12:00 and 1:00. Very long lines.