I still remember first watching this show when I was younger and the show just premiered on Netflix and loving it so much. I just loved George and Harold's pranks on the school, the teachers and especially Mr Krupp.
Sure the humor may be a bit too "toilety and inappropriate" and the characters, let's say Melvin for example is just a bit of a smart kid and he wants to attend his dream school so he acts snobby to others to achieve his goals stereotype but he was the same as that in the books as well and the show is trying to stay true to the original books by Dav Pilkey whilst adding new characters and new features like (I actually find her rather controversial) Jessica, who is obsessed with her hair or what she calls, "har" and the Sophies (I read the books and I don't remember them making any debut appearances) and the humor isn't just toilet humor, there's 4th wall breaks and other stuff.
Heck, even as someone who has almost never bothered to rewatch any shows or anime and only either burns through the first episode and then completely stops, I still rewatched this show (I'm only in Season 2 right now, where Melvinborg and Melvin dominate Jerome Horwitz) and it seems funny even with my broken asf humor where if anything happens + vine boom and amogus sound, I crack up.
Personally, it's a 4.5/5 but if some of the characters weren't so annoying (Looking at you Jessica) and Captain Underpants wasn't so idiotic and was a bit more heroic like in the books then maybe it'd be a 5/5 for me.
Overall, if you're at least 6 to 12 and a fan of the books and the movie, I do recommend this show, not highly suggested but recommended.
-A random girl on the internet