Probably there is a "best" airline ,and many bad ones.
Any airline you can get a job with is a good one until a better prospect arrives.
Conditions ,pay etc help ,but really ,is an extra 20 grand or so worth it if your in a place you dont like.
I bet many pilots would prefer to be flying with a company that suits there life style and family situations ,but have to grab an opportunity somewhere else.
I think in Aussie flying with qantas (internal) and Virgin Blue couldnt be beaten.Totally non conjested skies ,great climate,a breeze to drive to work etc ,and if its only 100g a year so what.
Qantas international same as rest i suppose but they dont have trouble getting pilots as does any other airline for that matter.
As before ,the best airline is the one who will employ you