I'm actually torn. When it comes to the narrative, the settings tend to be very different. In anime or Japanese Dramas, a lot of plot does happen in school with a few things going on here and there out of school.
In American cartoons or movies, a lot of the action happens OUTSIDE of the school, and some scenes take place in school (so the opposite of the above). Usually American shows with teens have a lot more varied settings outside of school too than in anime (Buffy, Sabrina, Teen Wolf, etc).
I do agree that in anime/Japanese school settings, the characters can be very diverse in personality while in cartoons/movies/American school setting, there are always some kind of stock trope (though Spiderman Homecoming was a breath of fresh air when it came to avoiding the cliches). There is always the stock jock, stock popular brat, stock, goth, stock nerd etc etc. Sometimes shows reveal that these tropes have more personality than just cardboard cutout of a stereotype but it doesn't change the fact the stereotype exists.
However, I do like that a lot of action for the teens DOES take place outside of school. I like that there are a lot of interactions with family, friends that are not related with school and such in shows set in America. So while the characters may not be as intriguing, the plot takes a lot of turns thanks to the variation in setting and location.
So it's...hard to choose for me. It really just depends on the story I'm reading/watching. As a person, I do prefer American schools because the idea of Japanese school sounds REALLY LIKE A LOT OF DAMN PRESSURE TO PUT ON A KID. But that's just me.