yeah i like MX5021 because of the weight of vocal. and especially lower mid.
i found myself addicted to lowermid richness now a day.
any things sound less on that will automatically rejected.
such as stock koss. and that's why i go mod it.

you can hear more detail on 6021 because it's slightly emphasis on the bright side, hence give you impression of better detail. that's true.
but i just love more meaty mid. more solid more thick mid range. (don't get me wrong, not muffle type of vocal like 4121)
and that's the reason i got HD. =)

bass on 6021 and 5021 seems both fine for me.
6021 has more surround feeling as it using sort of inconcert thingy to produce surround sound, and stage like speaker setup.

let say we number the driver from top to down, 1-6

driver 3,4 produce mid
driver 2,5 producing mid + high
while driver 1,6 will produce brighter sound, together with mid+ high
so it will show a really obvious feeling of concert. not bad imho.
but for use as 2.1 setup which i listen to it not infront of it. MX5021 is better in my opinion.
i usually sit quite far from my speaker when i heard it. that's explain why 6021 is rejected. =) and AEGO M ROCKS on this.

kokearn
in that case, i do suggest u go for VS. ATP3 is a bit lack on gaming. the bass not enough oophmmmmmmmmmmmmmmm