Haven't used it, but it looks like an excellent tool that would make the process a lot faster with less room for error. For me though I don't do this adjustment often enough to justify the price tag. I have lowered the action of a good amount of saddles, but I've just done it free hand without issue. You just need to make sure you sand evenly when doing free hand.
"Success grants its rewards to a few, but is the dream of the multitudes.
Excellence is available to all, but is accepted only by a few." - Christopher Parkening