I am only level 57 but I like using it during trash pulls or out solo playing. Once I have all my dots up, and painflare/fester is on CD, I like to fire off ruin 3. My ruin/ruin 2 hits around 350ish whereas ruin 3 is smacking 500 with crits at 750. Is this optimal, probably not, but what the heck, my mp regen is a lot higher than before Heavensward.