i love my 6xx, i daily my 800s now, but i had to eq up the bass a fair bit. Stock i think the 600 series is the best. Always disappoints me that i feel like i have to eq the 800s, sound stage is amazing though.
I never really understood speaker-like soundstage, maybe i need better speakers
meanwhile i think the xm4/5 are the least comfortable i’ve ever worn i guess it each their own
either 6xx/hd800s