Ok, so I'm going in depth here. ugh so I love both groups, and EXO is my bias group, I love them. And BTS is AMAZEBALLS JUST YAS.
However, who's the best choreography?
so, both groups are different styles. BTS is more hiphop/krump kinda like. EXO is more hip hop/jazzy/M.J style.
so its really hard to find who's best because they both ace their genres really well.
looking at this unbiased, I'd have to give it to BTS for being more concise. They are on point, and give they're performance a lot of energy.
HOWEVER: Who's more creative? I have to say EXO. BTS's chereo is intense, but EXO's is creative. They had to somehow find a way too chereo all those members, its was and still is crazy. (the one thing I love is Kai's energy whilst dancing never dies and he's always smiles and he's so hot and I'm super biased)
(I think also, EXO focuses more on singing (and looking beautiful), and they have beautiful singing voices.)
BTS: Focuses more on intense chereo and cool swag, and they have LOTS of swag, which is another reason that makes their dancing more noticeable. They are very into the hiphopness, and really capture that.
so all in all, BTS wins. BUT both groups have their good and bad points.