Mcdavid is slightly more skilled and faster. While Crosby has amazing skill along with tremendous strength and a desire down low that cannot be denied. I think both have equal hockey sense and equal acceleration but Mcdavid's top end speed is faster, but we must not forget how fast Crosby was when he entered the league. Crosby has the better shot at this point but that was something he worked on. Crosby worked on everything he "lacked" in especially the little things like faceoffs and improving his two way game.
If Mcdavid has that desire and it looks like he does he could be something else. I don't expect Mcdavid to be the player down low like Crosby but he'll be the bigger threat off the rush maybe make his living off the half wall. Mcdavid is also gonna get stronger and possibly not done growing. Crosby is what 5'11" 210 of solid muscle. Mcdavid looks like he could top out at 6'2" 210-215. Man both are just great players Crosby is still probably the best player in the world for the next 2 to 3 seasons, but Mcdavid will take that crown. Really hope Sid's concussion problems don't effect his career in the long run. It would be a shame and all hockey fans will miss out.
We're lucky to have Mcdavid as well as some of the other tremendous young talent between Eichel, Matthews, Ekblad, Laine etc. I could go on but the talent level in the league seems like it's taking a jump. Getting those 5 players especially within 3 drafts seems special, rare or unusal. Usually players of this caliber who can just step into the league as teenagers happen once a draft or every other or even once every couple drafts. Just my opinion though.