Both work very well. The choice is really a playstyle preference.
/Rad has higher debuff values but they are mainly toggles. /Rad has a self heal.
/TA has lower debuff values but they are a little more end freindly, can be stacked with enough +rech, and they can't be detoggled if you are stunned/held/slept etc. which means that Audry, Creepers, and flaming oil continue to benefit from the debuffs even if you are temporarily incapacitated. You don't have a self heal but I never found one to be needed. Spirit Tree worked well enough that I never needed the medicine pool.
-Insanity is doing the same thing over and over again and expecting different results. - Albert Einstein.
-I do not feel obliged to believe that the same God who has endowed us with sense, reason, and intellect has intended us to forgo their use. - Galileo Galilei
-When injustice becomes law, resistance becomes duty. - Thomas Jefferson
/TA has more synergy with Seeds of Confusion; you can use Acid Arrow and Disruption Arrow to lower Confused targets' resistance and defense, without lowering their ability to hurt each other. /Rad can't do that. On the other hand, I expect that /Rad would be better at dealing with EBs and up.
Arc #40529 : The Furies of the Earth
Which of these causes moar chaos and mayhem? I love my Earth/Storm, debuffs ahoy, I make Nemesis my b---hes with all the -res and -def.