Two similar players in the defensive zone, two different players in the offensive zone.
These guys are two of my favorite young defenseman in the league. Playing a ton of minutes on terrible teams, they've been very poised, solid, and look much more experienced in regards to their play than they actually are. Schenn has been playing with Kaberle for most of the season, though(before he was traded), so he did get a little veteran help each shift. Hamonic, with the other hand, played with another somewhat inexperienced player in Andy MacDpnald, although he is a very, very good player, and is currently carrying the Isles defense with Streit out.
They both play a rugged style, as well. They're physical, can be mean, and they're willing to drop the gloves to set off a spark or protect a teammate. They can clear the crease, and then they'll deliver that big hit every few games, to let their presence be known.
It's their offensive potential that sets them apart, imo. Hamonic looks to be much better in the offensive zone, and has a much better shot, and better vision than Schenn. That's not a knock on Schenn, though, who wasn't drafted to be a threat. He's a pure shutdown defenseman who can put up probably 20-30 points in his prime due to his solid outlet pass. In terms of player comparisons, here's who I would compare these two to(note that these are what these players could become of their expected development process goes as planned):
Hamonic: Shea Weber-lite
Schenn: A meaner Robyn Regher