As I may be baised due to my love for manga, Claymore is one I hold in my top 5 of all time. Due to its great story telling, art style and depth of female lead characters.
I really enjoyed how Yagi told the story in parts instead of short chapters. The story at times can be complex but once you tie it together it has twists and turns that make the world come alive and draw you in! Ths symbolism , lore and lessons are those of any top tier shonen.
I reccomend it to one of my good friends and loved it, hes not a easy guy to persuade but once he started he never turned back.