I am a relatively new Amsoil user, under 2 years, and although I agree it is a good oil (I'm not trying to start a 'who is better' discussion) I do like to read up on the different synthetics and their ratings/comparisons. All the ratings and comparisons I see are based on -new- oil. What I want to see is how well the oil holds up after 20,000+ miles that Amsoil claims. I am using Series 2000 0w30 which Amsoil states can last up to 35,000 miles or one year (with a filter change ever 12k or 6 months). Are there any other long-term comparisons out there for Amsoil, or any other synthetic? What I want to see is how well the oil protects after 25,000 miles and one year of use. This would be the ultimate test, and really should concretely prove that Amsoil can handle these long intervals. BTW, I am about to send my first batch of Series 2000 0w30 for analysis with about 10 months and 12k miles on it. I will post the results in a few weeks.