Even though I have a metric crapton of math training I am NOT going to drag it out for stuff like this. Not for me, you, or anyone.
I use the "common sense" math training. This is where you look at the big picture and say "screw the details"
If you are solo, could be a toss up. Could depend on the AV/Boss and their particular power sets. So, unless some uber geek who has done intricate testing (math analysis is not enough, you gotta test. Just ask a certain submersible captain. Oh wait, nvm) But there are threads of people who test powers and if you want to explore their work, have at it. For solo, I would go with feel and fun.
If you are on a team... What makes more sense? Not hard. A little extra DPS from one person... ORrrrrrr A Res debuff EVERYONE can take advantage of? Yeah, it's like that. And not a single derivative needed...