No Rad armor is way ahead Dark armor. Dark badly suffer of end problems, Rad don't. (I know Theft of the essence proc, but it's not enough in final balance). The small ticks from damage aura doesn't match with the burst potential of these proc'd pbaoe.
I tried both, wanted to love Dark but Rad is just better.
Anyway I'm just saying that many people miss the aoe potential of Rad armor because they don't get it:
you got 2 large (15ft and 20ft) fast animating pbaoe where put like 8 damages procs (chance to proc 90%), that recharge almost every pack (thanks to rech buff in beta decay).
Consider the heal as a secondary effect of a mini nuke. (at 90% res almost everywhere, it's enough).
From the years of playing, this tank was the strongest scrappy/tanky combo i've run. After throwing 3 or 4 of these aoe, i just had to take care of bosses (+4/x8 oc).
And that kind of slotting doesn't interfer with the-where-to-put ATO sets problems, at all.
But, if it's Pylon numbers you're interest in, yeah maybe take another road.