Anyone interested in securing their bike with a disc lock might want to check out this review of the lock by Webbike World:
http://www.webbikeworld.com/r2/motorcycle-lock/xena-xx10/Not only does the review contain a video showing how the lock works, but it also has a link to all of the other motorcycle security devices that they have evaluated.
I have purchased some of the items that
Webbike World has evaluated in the past and I think they are right on the money with most of their comments.