This post might be helpful too:
http://www.bikeforums.net/showthread...2012-Kona-Jake
I've got a 2013 Jake, but I race on a 2008 Major Jake with cantilever brakes, so obviously IMO disc brakes aren't that big of a deal for racing. A lot of people had problems with disc in extremely muddy and/or sandy conditions last year, but a lot of other people raced with discs and loved them. I guess it depends on course conditions.
CX Magazine reports that only 6% of the people who responded to their survey used discs at Nationals last year. That was one of the places where people using them had problems, so maybe those not using them that day knew something. In general, US pros seemed to like them last year, European pros not so much.