How exactly do zetas work ?

I like to share my experience that Barriss (if you already have her at 7* and high gear) is pretty awesome as a healer. But I agree with Ghost, I'd keep it to my arena team for now, until I have plenty of Zeta to spend...unless raid damage is more important to you than Arena Ranking. Then again, if you can still place first with what you have, why bother, yeh? I get it, I get it. :)