I'd like to know too. Spotted them in Boots and fancied one but they weren't that cheap and it looked like you had to buy refills too. So they'd have to be a lot better than one of those four sided buffer things. I really like using those but like you say they're a bit tedious.
I can't wear nail varnish because it makes my nails flake and crack a few days later. I have bendy and easily damaged nails.
The buffer does a really good job at removing ridges and making my nails shine. However, a few days later, my nails start to crack and flake, and then look considerably worse! So based on my experience I would say not recommended if your nails are weak, which is a pity because I just want clean, shiny nails!
I saw a JML one but it was for skin and nails (more for feet I think) it was £15, so half the price of the Revlon one.
I had one nail buffed by someone at those pop up stands in a shopping centre (they catch me unawares and I'm in) My glossed nail was really nice, but they buff like lightning and I can't be doing that 10 times.
I bought one of the Scholl ones. What a complete waste of money. It takes two batteries, the moment the buffer touches anything, it stops working. So I got new batteries, same thing. So when I Googled it, everyone else seemed to have the same problem.
I didn't take mine back as I bought it at a Chinese shop, much cheaper than they are normally sold for. I am quite sure it is original, as those who bought them at much higher prices in other shops, have the same problem.
They aren't cheap either. Don't waste your money on the Scholl one anyway. but I do have the Scholl foot buffer and that works well