I've been playing with the sunsinger since level 15. Radiance is amazing amazing in my opinion. It reduces damage taken, reduces skill cooldown, and increases the damage they do. My grenades have a 29% faster cooldown from gear(I want this much higher). With radiance.... it's about a 3 Second cooldown. This plus the skill in the far right that gives grenades a burn effect, and the skill the boost burns, it's pretty powerful. As an example, in PvE I find myself generating upwards of 20 orbs with it. In PvP, I may only get a kill or 2... but it can be used to kill yourself from dying.