I am running a Stiffi MF barrel on my Etek3. No complaints. The paint goes where I want, so it seems to be doing exactly what it's intended for. I cant comment on sound or any of that other jazz. I cant say I have ever noticed one way or another.
I started using Stiff tips on my freak back in 03, I bought that strictly based on the CDI factor. I hadnt changed the insert on my freak from 2002 through 2005 so I decided that I really didnt need to have a barrel kit with a bunch of parts. I just wanted single piece barrel and I cant find a fault with Stiffi. I think I'm running a .685 on one gun and a .687 on the other. Regardless, it's the Indian, not the arrow that matters.
It is not advisable to venture unsolicited opinions. You should spare yourself the embarrassing discovery of their exact value to your listener.