Very good points guys!

Although I love the Amsoil oil, I must say that it is kind of expensive and hard to get sometimes.
I will say that I am considering Mobil 1 in the diffs and tranny because it is so readily available at Wal-mart/Sam's club.

While I see your points, I must say that I don't see a problem using the Amsoil in the motor over 5,000 miles. If you follow the instructions, that would be a filter change every 7,500 or 6 months, whichever comes first and a full oil change at 15,000 or year.
I think in a normal daily-driver use engine, that will be good enough to get the suspended particles out of the motor. Now I'm not talking about a Fram filter here... I'm saying a quality filter such as a Mobil 1, Wix, Hastings, or Amsoil filter.

John, very good site, by the way! I love it when they test out the different products to see if the company claims are really accurate!

Maybe I'm being too trusting of Amsoil and their extended interevals? Either way, I guess I'm gonna fall somewhere between the really long extended intervals and the normal change interval. One thing is for sure: I won't be changing it every 3000 miles. I think this is a waste.

Thanks for the input, I appreciate the friendly debate.

Joe