Strands of Astral Power. Worth it?

[Tuidjy]

What do you guys think about the global "Strands of Astral Power"? In my current
game, I have drawn too much attention, and my only chance for survival is to
turtle down and hope the neutral nations decide that my enemies are getting too
strong. I am considering "Strands of Astral Power", because I know that "God's
Wrath" will hurt people outside of my dominion and they will rightfully turn on me.

Now, I am pretty sure that it does not attack outside of my dominion. I have
tested it as well as could in the SP games I have around, and everyone I have
asked has agreed. But is it worth casting?

I understand it only attacks mages, and that they get a MR check. Will penetration
items on the caster help? Will extra natural levels? What about astral boosters?
As to non-astral enemies, will the mind burn benefit from penetration and extra levels?

Anyway, I am absolutely ignorant about this spell, and both the manual and the
in-game description fail to answer many of my questions. Have you ever used it
in Multiplayer, and what did it do for you?