Just a few thoughts after no more than 8 hrs listening.
I'm not hearing what I'd call an overly dark headphone,warm to me,I found 650's a little darker,but given a few days and praps I'll change my mind?dark headphones for me were my old 80's 600ohm beyerdynamic 990's,dark as in sonically being in a 50ft square room holding a candle lol
The 400's have very slightly forward mids,not so much to unbalance the sound,but just enough to make music exciting when needed.
Soundstage is not huge,but plenty big enough for me,width,height and depth are fine,not going into detail yet,grown wiser with age to develop opinions on sound over a little more time,suffice to say I love these so far tho.
I find the black canare cable ok,not really annoying me in use.The 400's feel pretty comfortable,well made far as I can tell and I like the blue!
I find the weight of these fine,but wouldn't be crazy bout anything heavier.