Quote:

but that means you don't think a smoother idle, longer lasting engine is a reason.



Assuming proper oil changes, the increase in engine life between Syns and Dinos are practically undetectable. Some of the results I have seen are so similar that no clear advantage can be given to either.
As far as the smooth idle goes, I suppose if you can justify spending 2x as much to get a smoother idling engine that lasts the same amount of time, so be it.

How many people keep their cars past 100k anyway?

"If you are flammable and have legs, you are never blocking a fire exit" -Mitch Hedberg