For those of us who wonder how it works have a watch of this brilliantly simple but demonstrative video from Honda. The DCT doesn't seem to induce any judder, indeed it keeps the bike smooth through shifts.
The shift paddles are operated by the left hand. If I was to ride a bike with DCT I'd rather the paddles were in place of the normal gear lever, i.e. operated by the left foot. Although, frankly, I'd still rather have a manual gearbox.
Thanks to Colin for the tip.
Matt