Overall, I'd give NCL's Sun a solid B. There were some things that were exceptional and others that made me scratch my head.
The staff was friendly and warm. Everyone tried to make us feel welcomed. Some staff members tried to connect on a more personal level. However, there were times when I realized that the Sun is a smaller, older ship and maybe some of the staff were on this particular ship to get more seasoning. That's acceptable and understandable.
The food was good. Some of the meals were incredible and others were average. Breakfasts were very good to me but I also enjoy a nice breakfast. I chose to pick from the buffet and enjoyed eating outside instead of sitting down for bigger breakfasts.