Replying to New kickstarter follow focus

just saw this, looks like a pretty cool and promising idea, definitely useful for someone wanting a small run n gun type rig

http://www.kickstarter.com/projects/microfacturing/lens-focus-shifter-lens-mounted-follow-focus?ref=category

what do you guys think? obviously it won't replace a nice rail mounted one with hard stops, but i could see it being popular with a certain crowd