There isn't much to say about Kenja no Mago, so I'll get straight to the point: if you're tired of the reincarnated OP MC stories, ignore this Manga.

The story, the lore, the setting and the characters are all by-the-numbers cutouts and, in terms of originality or uniqueness, the Manga doesn't have anything going for it. Comedy is slightly off, although I did chuckle a few times (mainly due to the exaggerated faces), but other than that it isn't that funny.

Art is quite good and detailed for the most part, and action scenes are portrayed as well as in any other action manga.

That being said, Kenja no Mago is a meeting of all the cliches: OP MC who steamrolls through everything without any true struggle (at least so far I suppose), a whole heap of maidens fawning over him, pretty generic setting and lore of the world, and that's really it. Nothing new, nothing unique, but if you enjoy these stories just for some quick giggles and power-fantasies, it's pretty good in that department. If not, you best just ignore it.