I'm not trying to compare in anyway. I want to start using one brand of oil and I'd like your opinions. I can get Amsoil 5w-30 for about the same price as Mobil 1 5w-30. Which would you choose? Both are good oils. I like the convienence of M1 but I like Amsoil's customer service. They will answer any question you throw at them. My orders also hit the front door in 1-2 days. I like Amsoil's thicker viscosity too. I think both are very close right now.