Personally i like turn evil over the other morph of the fighters guild rune ability only because it lasts 20 seconds still but even that doesnt feel good enough to justify it really and only works due to me playing a tank and wanting to not have to back up to reup it as much for my teammates who dont have minor protection. personally i think if it had its cost increased a bit but lasted 30 seconds and MAYBE was made slightly larger so your ranged dps and supports had more room to move around in it, turn evil would be really good and a valid side choice for those who want something for those in the backlines while the other works great if you lack minor protection and or endurance or just want a nice ground dot heal.