How many use 'Rig for Silent Running' ?
 

Question is in the subject. :D

Also, when being chased by a torpedo(s) and launching decoys / knuckling has 0 effective, what are some other good methods to try?

I almost always go silent. It reduces even further the passive detection risk, which is alway good when stalking.

I use it when I have not been detected.

as to what to do when a torp is launched at you, I increase speed to 10-20 knots to try to get out of the torps acquisition cone when it goes active, launching multiple decoys, I then try go as deep as possible and slow to 3-5 knots.

usually works, but YMMV

Rigging for Ultra quiet reduces your passive sonar signature by 2~3 db. Reducing speed below 5Kt can further lower your signature by another 3 db. For sure, that can make the difference between detection and stealth. The instant you reload, raise speed above 5Kt, or make any kind of repair, you are no longer ultra quiet.

I have to say that decoys and knuckles work well for me,

I rarely use it, instead I immediately switch to 5 knots when entering 3D world.
I think silent run can somewhat get you better enemy detection numbers for your sonar, although I don't see a big difference. And to my experience that's the only advantage, I cannot remain undetected for longer time with it.

I think silent running would find use on noisier subs (skipjack and '68 permit).

It is almost always the case that you'll be picked up on active sonar before they hear you on passive sonar with the more modern subs.

So, for the vast majority of scenarios, silent running is next to useless in my book.