Which champs benefit the most from the Axiom Arcanist rune ?

I use it almost always, obviously it has better stats on single target ults/very long ults. One prime example would be Shen, I rarely if ever see it used on him and I don't know if I'm making the wrong call. (It refunded 285secs for 25min game on my last use)

Then again, I use it almost always as I miss skill shot like there's no tomorrow, so my fav tree is sorcery to get AH.