Who gets the Toughest Matchups: Defensemen

I hope you're familiar with the concept of "Quality of Competition" at behindthenet.ca. (You can find a short primer on it here.) At any rate, I wanted to post the rankings for defensemen on every team through Saturday's game. This list uses opposition Corsi +/- (shot differential) rather than goal differential - shot total is less-influenced by luck, so it gives a better indication of how a player has performed:

One thing I like about "Quality of Competition" is that if you don't watch a team very often, you can get a quick sense of how that team's players are used. Did you ever wonder if Mike Green's ice time is a little soft? Did it seem weird that Rob Scuderi - who has 18 goals over all levels of hockey since he started college - was a good free agent pickup? Were you concerned about who would pick up the slack after Kurt Sauer was injured in Phoenix? Well, probably not that last one - but Quality of Competition gives you insight into the first two...

There are some imperfections in the system - it's difficult to compare across teams, and even within teams, players who have a shutdown role but also play so many minutes that they're bound to face some weaker competition, like Jay Bouwmeester, are underestimated. But by and large, as long as a player plays regularly, this is a reliable system to compare players on the same team - I'm interested to hear if any of the #1 and #2 defensemen above are misevaluated in terms of their usage this season.