It’s definitely under rated. Remember when everyone hated it and thought it was the worst thing around. They also hated the anime because of Japanese Asta’s annoying, ear splitting “AAAAAAAAAHHHHHHH!!!” screams. Then everyone started loving the story and anime because they realised it was a good story.
My opinion is that it’s really good and it’s what that load of crap Naruto should have been. Yes, controversial opinion but that is what I think. The story is a lot better, the characters are better written, the characters are actually likeable, the girls aren’t useless, and Yuno, the rival and best friend of Asta isn’t emo and doesn’t want to kill him. Also the author hasn’t turned the story into a sexual fantasy about Yuno, like that untalented hack Kishimoto turned Naruto into a sexual fantasy about Saskue.
Again, I know this is a controversial opinion, but it is what I believe.