Originally Posted by
Gray Lensman
That also depends on personal taste. One Punch Man is in many ways a treatise on depression, disguised as a comedy and dressed up as a superhero. It's excellent, but might not be to everyone's taste. Although for those who do like it, it is actually considered by many to be ONE's lesser work, with Mob Psycho 100 being better. But again, that's a matter of taste as One Punch Man does its comedy very, very well.
My Hero Academia is more traditional superhero fare, although with a lot of Harry Potter mixed in. And while it doesn't break new ground quite like One Punch Man, it does have more depth than the surface suggests and more importantly, it does what it does very well. The main reason I suggested it first is that it is probably the easiest entry point into manga for a superhero comic reader of anything I have seen or even heard of.
One advantage both manga and creator owned works have is that the writers don't change. You won't pick up an issue or trade and wonder why is Deku or Saitama suddenly acting so strange? They aren't going to be shoehorned into the plot or get written by someone who hates them and wants to trash them to push his fave instead.