I started this past IB with Stormcaller and then Sunsinger, but finished it up doing mostly Voidwalker because I was doing a lot better with it than the other two sub-classes. I was getting killed quickly with Stormtrance and would only get a rare multi-kill, so I gave up on it (worked much better on the Control or Rift IB since people were grouped up more often). Then, Sunsinger didn't work out too well because I just don't know how to do well with Radiant Skin (and do worse when using Fireborn in 6v6). Did best with Voidwalker even though most of the time my Nova Bomb was used to kill a single enemy that was using a roaming super or had heavy ammo (though, did get some 3+ kills at the heavy spawn).