Years ago a friend of mine got a set of wheels and used a salvaged clothes washer motor to build a sharpening station. We practiced sharpening knives to the fanatic level, putting the edges under a microscope after we were done to see how tight the edge was and how polished the bevel. I ruined a DWO pocket knife trying to lay the edge down too far (using a wheel you can get an infinitely shallow bevel, to the limits of the blade). I ended up creating a burr that was 1/16" wide in a solid ribbon along the length of the edge. When it broke on the polishing wheel, the edge was pretty much ruined, and the tip was now exposed when closed into the handle, making it a dangerous pocket implement. Yes, you can overdo these things, but it was a learning process, and probably not a bad way to spend $30, though I'd have rather done it with scrap.
More recently, I acquired my own set of wheels and mounted them on a cheap bench grinder. I prefer the wheels to be turning away from me. It makes it easier for me to see the edge near the top of the wheel that way. I've sharpened everything from a little SAK classic to my Leatherman Wave to big butcher knives and even a friend's beat up machete. That machete was a good challenge, it had been abused for years, and you could just about draw the length of the edge across your bare arm and not cut yourself. There were so many dents and chips in the edge it was more like a saw than a blade. I worked it on the grit wheel for a good 5 minutes on a side. When I was done I had a nice clean edge with a uniform bevel on both sides. I put it on the rouge wheel and when I handed it back to my friend I warned him he would need to be careful with it. He took it out and started whacking palm fronds and when he came back he had a nice big grin on his face.
It does take a bit of practice, but I found that I got the knack for it faster than I did for using stones. I have an edge on my Leatherman right now that is sharper than I would've thought possible. It'll cut raw bread dough without wrinkling it, which is always a good test for how sharp an edge is.