from a visual perspective, I wish he felt the pressure a little better. He tries to make space for himself with his body to carry the puck with one hand on his stick a lot and seems to lose it too often but just a little more panic in his game would let him avoid that.
however, he's obviously worthy and a hell of an upgrade, and it's nice to see one of the dmen smashing bodies at the blueline
I have no issue with a top pairing of Rielly-Muzzin, that's respectable by any standard. I think Muzzin looks better on the off side than Rielly: he's the shooter so better to have him offset when we have the puck, he likes to have one hand on his stick anyway so keeping the offensive blue line on his off side seems a little more natural for him than most, and he likes to use the body to defend the defensive blue line so stick placement matters a little less