Amsoil is basically snake oil. It's not API certified, which means that they're not confident enough in their product to submit it for certification. If they're unwilling to certify their product then there's no way I would use it in any engine I own. They offer a lot of marketing hype and not much else.
I own a 1998.5 dodge/cummins that has 312,000 miles on it and it's used shell rotella T since it's first oil change. Stick with a quality dino oil and your engine will run forever. Forget the snake oil stuff like Amsoil, there's nothing good to be had from it, it can only decrease your engine life.