I’ve got a squadron scribing tool… I wasn’t happy with it a first; I had troubles with uneven lines and gouges. Then I found what I thought was going to be my superscriber… a broken micro end mill (~1/32") that I found in the junk drawer at work. But then I went back and did a comparison with the squadron tool, and they’re about the same now (somehow my technique with the squadron scriber drastically improved).
The trick with the mill is to line it up just right. I also tried it with new end mills, and they didn’t work nearly as well. I don’t know if it’s because they were larger (~1/16") or because they weren’t broken.
The best thing about both of these is that when you do it right, the material coming off coils right up, and there’s rarely any need to sand/scrape off ridges.