Never used one. They look interesting. I know I haven't seen any in any hardware stores. I'd like to try one, see what they are good for. Or see a video of one in action. It's like bow bars on a chainsaw, never ran one, I have never seen one in the flesh so to speak, couldn't figure out what they were for, how and when to use them until I saw a video and read a little more about them.
My back is binary. Works fine/absolutely doesn't work, no middle ground. Been out most of the week, can't do much. Know I can't run a saw now or pick up any sort of round, even if I could picaroon it closer. Maybe one of these tools might help me avoid issues? Don't know. It doesn't go out on me doing normal work, it is just bending funny, reach down to pick up like nothing, a dropped whatever, or like the other day, just woke up in pain with some disks moved the wrong place or small rupture or something. Original accident was 12 ruptured, absolute teh suck.