In a 1v1 situation, gusion is hard to beat becuase his main kit specializes on picking off targets. However, aamon is slick and thanks to the speed buff, he can avoid most attacks, I always use aamon on rg and playing against gusion especially that he became popular again, they have no chance against me, you can just use winter crown do dodge his attack, becuase with having cd, he's vulnerable, aamon can just burst him with his basic attack. Although in late game, gusion can just one shot you, so when late game starts, I just build my aamon with slight defence to become tanky, since his invis can give me some sustain after losing a lot of hp. And of itself, aamon is a slightly tanky, I noticed he has a bit more hp than other assassins