I went from Mobile 1 to Amsoil and now I use Eneos so far liking it. I still use Amsoil for my other fluids but started using Eneos engine oil for about 7 months and loving it so far. Will try some oil samplings when I get back for a few months and compare it with Amsoil. I usually change my oil every 2-2.5k miles because I drive the piss out of the car and I love my stock motor lol