I to use either Amsoil or Mobil 1, I change my filter every 3-4 thousand miles and top off what I lost with the oil filter removal. I've sent in my oil sample in to be analized once a year, for years and have NEVER had abmormal wear in my motors. These is the same way to see abnormal wear in jet engines, too.
Now if I get a used car that I want to clean it out out (cardon) I use SEA Foam.