- music
Well, that's a big topic, in general, but in short terms:
Top of my head, and also probably to be edited later, but ExO and BTS kind of hold the tie for the best songs. With ExO leading. I only consider BTS until 2020 because everything after was a disaster and even before 2020 their music wasn't that good. On my list only BTS's old song have been included.
ExO leads also because BTS's production is bad, only Jungkook was singing back then, now not anymore, sometimes Taehyung, but then he started with his whispering and screaming like a cow, Beyonce style, and the others don't bother taking singing lessons. They leave it up to the fans, who would listen to anything.
ExO on the other hand, has the better production and you can hear the voices.
Since BTS didn't had any singers besides Jungkook, you have to mix up everything, in order to make it seem, as if the others are singing as well. This doesn't justify the horrible production, though.
While ExO has, whtever BTS released, BTS doesn't have things like Baby Don't Cry, Overdose, ko Ko bop, Overdose. They were two more.
SKZ has the better singers, because even with some weak members, you can still hear different voices.
They don't have the super duper songs like BTS and ExO do, they lack the good quality songs, it's somehow similar to what I was writing yesterday regarding their shows. SKZ has the members capable to do more, but not the personell.
Will update later. Got to go.