What percentage of PageRank is lost through a 301 redirect?

Matt Cutts explains how page rank and 301 redirects interact.

 

Hmm, I had actually never considered that it might affect PR. :S It kind of disturbs me that it is identical to a link and could dissipate accordingly. I really don't think it should have any affect at all.

I know he's trying to make it seem like it's unimportant and makes no real difference at this point, but he's comparing links and the redirect.....versus comparing a redirect and no redirect or link at all. What I mean is....for example, someone who redirects their .blogspot address to their main domain as a .com, is essentially going to lose a little bit of PR juice instead of it being a non-issue entirely.