As a beginner knife-knut, and consequently a novice sharpener, I'll venture my $.02.
All views presented are excellent. Let me just say that as a 40-something office worker with more work (and now knives) than time to sharpen them, I appreciate any scraps of information I can glean from others.
Desert Rat and Snick... it's good to know I can count on a brick or sidewalk in a pinch... I hope I can get proficient enough to do so in the near future. I guess I need to use the edge of the curb for those recurved blades
I didn't grow up among knife enthusiasts and I don't know of any around me at work, so practicing or asking other people in my white collar office for their opinions on knife sharpening or edge testing is likely to raise more than just an eyebrow or two.
Time to practice at home is at a premium because of family matters... I hope anyone with kids can appreciate how difficult it can be to get a few hours to yourself without being asked to help with homework or "honey-do" things.
That being said, any novice will grab at any gadget that will help him/her get started with the minimum of time and effort. I'm not saying these gadgets are the means to that end... but to some extent they promise to be and that's all we have available to us.
If a 1-2 hour freehand sharpening workshop were offered around my area, I'd jump at the chance... but these aren't the kinds of classes they offer at adult ed or community college (at least not at mine).
Naturally, our most ready resource for information is the local knife dealer and of course the expensive gadget is what they'd be expected to promote... heck, to hear them you'd think that the idea of freehand sharpening is a popular myth.
So I welcome any sharpening tip I can get to hone my skills, be it a doodad, the instructions or hints on a box or website, or especially this forum. As you've all pointed out, this is a skill not easily mastered by looking at pictures or by a rote following of printed instructions... it's a very tactile experience that comes with practice and any aid that helps me to get there faster has my buck (for now).
The most practical tip has been to practice on some cheap knives first before committing my new preemo knifes to the stone. In observing this, I think I've avoided the heresy Desert Rat described of butchering a fine piece of metalwork in the name of education.
When you're short on time, there's probably no substitute for someone standing there and showing you what to look for and to do. Hope to catch a class someday maybe at one of those knife shows ... then I'll just have to figure what to tell the LEO I was doing with my knife on the sidewalk