Henry Cavill. Stephen Amell's heart is in a right place and he's a great guy, but he's a mediocre actor.
Cavill on the other hand, doesn't have an impressive resume and was wasted in MoS and BvS, but when he gets to shine, he is so. Charismatic. His role in The Man From Uncle is fantastic. When Zack Snyder gives him the opportunity to, y'know, act, he's very good. If only for his charisma.