Amsoil shifts nicer than the Syntorq, IMO. I think it's a superior oil, and it's much cheaper at the same time. I vote for Amsoil.

Secondly, whatever you choose, fill it up to the plug, then pour an extra quart in through the shifter. This will keep it from starving the top bearings and give it a much longer life.

 

I strongly disagree.
It's a well proven engineering principal that bearings submerged deeper than 1/4 of the lowest single ball or roller bearing run way hotter and overheat the fluid. I'm certain NV designed the fill level to the bottom of the hole because that's the optimum level.

Not sure what Amsoil costs but it's only $11/qt here for Syntorq

 

Ive run amsoil. And after a year/15,000mi it starts shifting hard. Then change fluid and its better, but a year later, its tough agin. After two changes, Im going back to Syntorq.
Thanks infidel for the link. I'm ordering tomorrow.