You can tell who has seen Colaiacovo play and who has not...the ones that don't try to quantify and quantify...with their "blah, blah, 23 or 24 years old...blah, blah, blah 6th ATOI, 6th in ATOI, not 5th in ATOI, 6th, always 6th...blah..." If comparing players talents were as simple as a numbers game we wouldn't have threads like this, we'd just go to nhl.com and look up which one is better...since these are both young defenseman that don't have much NHL experience you can spew all the numbers at us that you want but it won't do a bit of good because for your numbers have no statistical significance at this point in his career...
Anyway, to the matter at hand...
I've been a big fan of both of these guys over the course of their development and I hate the teams they currently play for...I think Colaiacovo is so much better geared for the new-NHL, he's not big, but he is one of the best skaters among Toronto's 17 or 23 or however many defenseman you guys had last year, he is deadly with the hip check (even to himself at times unfortunately) he has a lot of offensive potential, I know stats won't back me up, but every time I see him play it seems like he's either scoring or generating great offensive chances, he's very smart, he always seems to know when to pinch (which is never when paired with McCabe), there's really nothing not to like about him, if he's healthy, he's easily a top 4 defenseman just for his sheer agility alone...
Coburn might be better suited for the old-NHL, but he does skate pretty well for someone his size, I'd love to see him lay people out with that 6'5" frame more, I think he can be useful offensively too with experience...he seems a little unsure of himself at the NHL level, but like someone mentioned above, he's got 3 of the 4 "S's" just missing 'sperience...I say he really puts it altogether he could be top pairing on some teams, but I think that's a longshot at this point, I'd put him top 4 on just about any team in a couple years though...
I guess if I had to pick, I'd take Colaiacovo (on the Penguins, I can't bring myself to get a Leafs jersey, I guess I'll go Erie Otters instead)