From my investigation M1 and Pure one filters are both better as long as you aren't looking to push them for extended drains. Makes sense too. The Amsoil filters would have to let some of the smaller stuff pass through so they can go the advertised 25K OCI without clogging up. I'd rather trap the smaller stuff too, and change the filter a little more often. The M1 and P1 filters are cheaper too. win, win for me since I don't do extended drains. YMMV.