I like his vids, they're part of my indoor-training playlist. I favor the ones where the camera's mounted to the bike, not the helmet. Anyway, after seeing his vids I got Dashware myself. Takes a bit of fiddling but it was worth the $50.

I do find that the readings can drift around. Even if your GPS file contains actual speed, such as from a GSC-10 wheel sensor for a Garmin, Dashware still interpolates speed from the lattitude/longitude, evidently. Cadence readings can also drift, particularly when actual cadence is zero. Still, for entertainment and storytelling purposes, it adds to the fun of POV videos.

This one's one of my favorites, drifty readings or not: http://www.youtube.com/watch?v=JsdniW92GFQ (my come-uppance arrives about halfway through, courtesy of Mother Nature). At the end, when I stop, you can see the speed and cadence refuse to stay at zero.