I am using it in my 09 CVO Road Glide. I work’s very well. My bike shifts great and the gear whine is gone. I am using Redline Primary in the (primary).
I am running RL Shockproof in my FLSTS and it works great in that bike. I am sure it would work great in the 6 speed also.
I would have to say it comes down to availability and price.
Now if MolaKule would start making his oils again that is all I would be running in both my bikes. His gear oil and motor was the best I ever used.