So I bit the bullet and picked one of these up. I have to say, it is an awesome little addition to the tuning arsenal. I used my daughters four year old Koas as the guinea pig. No use trashing my Hero LT and ST :) The bottoms of her skis are fairly well scraped up. Doesn't help that she is a ski instructor for little kids, skis backwards for hours at a time, and goes over god knows what. After about an hour of work, her ski bases look like new.
I do have a couple of questions though. How often are you sharpening the stones and blade? And how do you get the gunked ptex off the corner of the stones easily? The brush doesn't pull it all off.