cptjeff
Reprehensible User
Using it still ruins the evenness on your edges, if your edges are even straight to begin with... which is unlikely considering how many bad sharpeners there are out there. Including a certain mail order "expert" that many rave about.
If you think the likelihood of taking a piece of sandpaper rolled over a cardboard tube, in a little hand-held device with little plastic gears can possibly not unbalance your edges, so be it. I'm sure your Powerbalance bracelet works well too.
The cylinder is wide enough that it tracks straight on the blade. Perhaps if you used a shallow hollow it might wobble back and forth, but if you're deep enough, it stays in consistent contact with both sides of the blade at the same time, and the length keeps it straight. That makes it carve evenly from both sides, unless you're being really careless and applying hugely different forces then it's designed to take. Not to mention the fact that it tightens down on the outside of the blade for tracking as well. Basic physics and a calculation of forces will tell you that much. Powerbalance type stuff is simply utter crap with no real scientific background whatsoever.
Your post really demonstrates something I absolutely hate, but is rather prevalent these days- completely unreasonable cynicism. People just assume everything is a sham, simply because they've seen so many shams, and don't want to believe any evidence that might make them believe otherwise, no matter how convincing it may be. I'm not trying to call you out specifically, but it is something that frustrates me in general.
I sharpen my own skates whenever possible, and am pretty meticulous about them. I always make sure to check 'em for evenness at several points along the blade when I get them done by someone else. Traditionally, that someone else has been one trusted guy at home, or a guy who sharpens them for a NCAA DI team. I know a good edge. And yeah, I use a skatemate, and feel that its use on a worn down edge helps more than it hurts. If you want to give me a good reason other than a claim of 'common sense' and a dismissal of my ability to recognize a good sharpening, I welcome it.