http://edition.cnn.com/2016/07/12/aviation/worlds-best-airlines-2016-skytrax/index.html
It's difficult to assess which airline career is the best. I think that service difference between airline careers are smaller than service difference between carriages in the same airline careers.
By the way, I've boarded airplanes operated by Emirates, Cathay Pacific, ,and ANA All Nippon Airways. All of them are listed in the best 10 airline careers.
But, I can't choose which is the best one.