I bought this as my first crowning file, so I can't really compare it with other files, but I have a few comments.
I decided to buy this because I had never done fret levelling & crowning before, and this looked like a good tool and safe to use for someone who's just starting. Meaning that I couldn't ruin my fret tops because of my lack of experience.
This is true, the file is pretty simple & safe to use. It also has it's weight, a comfortable rubber grip, a marked zone for spot crowning, and 2 sides that fit different sizes of frets. But these are things I might not be able to fully appreciate since this is my first and only crowning file I've had.
The depth of the curve of the file is more or less 0.020 inch (I measured this quickly with the MN string action gauge) so it should be good for low frets too. Yet sometimes it feels like even when there's enough material the file still slips away like it can't crown anymore.
My main complaint is the wider crowns (around 1 mm) and that sometimes I can't get the width of the crown evenly along the fret. I don't know if that's my own skill issue, lack of fret material, or the file itself. I know I'm not the only person complaining about the wider crowns.
All in all it's a great tool, because it's easy to use for a beginner and despite the previous problems I mentioned, all 5 guitars I've done with it play great. But with this safety and easiness you lose a bit of control over what you're doing. I kind of wish I bought SM's Original Z-file instead and spent time learning how to use it well, then maybe I would've had a better result now.
