I find it difficult to rate things like this, McDavid's explosive speed gives him an advantage over Crosby. However when the games on the line you want them both out there for their respective teams.
Yes Crosby has won more, however the teams were constructed much better in Pittsburgh. Ownership went out of their way to give Crosby and Malkin the leadership and experience needed with guys like Gonchar, Sykora, Guerin, Roberts, Lemieux... so he was definitely put in a position to succeed from the start.
Even Toews and Kane had help with guys like Lapointe, Campbell, Hossa, Madden.
Guys that had won or knew what it takes to get to the finals
McDavid and Drai had to drag this team to where it is by themselves, ownership and management have done an awful job (this offseason looks good however) in helping them develop as Players, and Leaders. The only player Management brought in that significantly contributed to a cup win or run was Lucic.
anyways... long winded way to say I think they are the same tier.
Edit: which isn't even an option for the poll...... "sighs"