Firstly 'Stihl' files are swiss made by Vallorbe, and yes they are good decent files. What I have found buying saws files is that all brands have their good & bad batches. Its the hardening process which dictates to a great degree how long they last (providing your technique is good & your not destroying them prematurely). Some good brands are Oberg, Vallorbe, Pferd, Save Edge, Oregon (not sure who makes them) Carlton, Sanvick Bahco, Nicolson,. Pferd have a very complete range & offer both a coarse cut & a smooth cut in their round files. I've even had GREAT results with a few dozen Taiwan made depth gauge files. All I'm saying is be mindful as ALL brands IME have good days where the files treated last long and have poor days where there not so good. And you have no way other then to uses the file to know this. The best thing you can do is have good technique as poor practice will severely limit a files cutting life. How you store them, how you clean them (file card, toothbrush etc) makes a difference too. I also take with a grain of salt opinions on file life, as to do so you have to presume the human variables are the same, which they are not. Helpful??...