Generating chances and creating turnovers. I don't know what the stats say but he had a few takeaways or just heads-up plays where he intercepted a pass or put himself in position for a contested or loose puck.
People saying he's slow or lazy or disinterested...what are you watching? Mantha is a tall guy and like Chara he's going to cover ground with longer, slower strides. He won't waterbug around the ice with elbows and kneecaps flailing around like a Sheary or Hagelin but I've yet to see him lose a footrace or be out of position due to speed.
You can see him looking for space and trying to anticipate where the puck is going to be, and therefore where he needs to be. He's moving efficiently and doesn't stop and start with a lot of direction changes, which appears "lazy" to those who think lack of leg movement means slow gliding. He's obviously thinking ahead to the next touch because he often makes the exact right finesse pass/drop almost immediately, or at the very last instant in order to draw the defense. His hands are elite.
IMO all of this is spot-on. And I can see how, if someone's a Vrana fan who's comparing Mantha's "lazy" skating style to Vrana's explosive style, the glaring difference would be annoying as hell. So yeah, Mantha wouldn't win a foot race against Vrana, but I think Mantha reads the play much better (and faster) than Vrana does, so he's better at anticipating what'll come next.
I think multiple people here have already compared him to Kozlov, which seems like a decent starting point. (I'm sure there are more recent and accurate examples, but nothing immediately comes to mind.) IIRC, Kozlov didn't use his size anywhere near as much as Mantha, and spent more time on the perimeter--whereas Mantha looks willing to use his size to get into tougher places. We're also getting Mantha in his prime years, as opposed to having Kozlov during the twilight years of his career.
I really like Mantha, and was very happy with the acquisition (even though it came at a major cost). So far, my only real issue is that, as was mentioned earlier, he does occasionally end up getting the same space as one of his line mates--as if he's used to being the guy in that position in that situation, where now he needs to get to a different spot in that situation.
