Simple, easy, fast, inexpensive
I have one of these, have for a couple of seasons. It hasn't given me a durability problem, although I suppose I don't use it super-heavily. I love the simplicity - if I'm being good about keeping my skis tuned, I just hit each edge a couple of times with the finer side of the file, wax, and go. 2 degrees is the only angle I have a need for.