Depends on which grade you are looking at IMO. I have my reason to believe that the Mobil 1 HM 10w30 is indeed superior to most of the Mobil 1 products and PP products. The reason I say this is because the pour point of the HM 10w30 is -54! This seems to indicate that this particular oil is indeed a Grp IV. Also, the HTHS number appears to be pretty good as well.