The reason Im so "negative" is because I have been watching these surveys for years and I can tell you without a doubt the same cruise line win the same contests year after year.
CARNIVAL wins the "best cruise line" award from Porthole year after year. Why?
I also happen to think the concept of "best" is a joke. Best for what? I am very fortunate to have sailed on almost every cruise line, and while one may be best in food or service, the same ship can have a few bad room stewards and you get lousy service.
A cruise line that is best in food may be worst in shore excursions. Is it best at what price? Carnival is the best cruise line for under $100/day balcony, if you like pool games and r-rated comedy shows. But if you like cabin amenities like big TVs, lots of stations, hair dryers, frgarant soaps, etc then you would like Celebrity better.
NCL is best if you like many dining choices. RCL is best if you like cool, state of thre art mega-ships.
Star Clippers is best if you like sailing vessels, Oceania is best if you like destination-oriented cruising.
Disney is best if you need great children's programs.
There is a tremendous amount of variety out there and that is a good thing. i don't see the need for contests, really. Its all objective - there is no best cruise ship.