Neutral fan here that likes both. From the above arguments, it really seems pretty close.
Try to imagine McDavid on those Penguins teams, and then do the same for Crosby on today's Oilers teams and you'd probably envision similar results either way.
McDavid, if he stays healthy, has a chance to open up a bit of a regular season gap in the coming years, as Crosby hits his injury-riddled seasons. Crosby winning the Cup in 09 with his great performance should help his side of the argument if Edmonton keeps having trouble as a team.