I got a Q701 for test.
I had short of time .... and don't want to run the burning in unattended.
Now after 25 hours a short review
Very clear, wide soundstage (like as the other 701/702), air between instruments, detailed, the tsstss of the brass very realistic, deep bass, clear highs (a bit better than the K701) - at some music the bass and bass-mids seems me a bit tight and realistic as the D7000
I use the mod Philips and the WNA MKII for the test - a short test with Marantz and Solo are nearly the same result.
This is only a snapshot, this could vary with time, but I hope not much
I like the Q701 sound as is now!
IMHO the burning in curve looks like an e-function as a cap is loading up over a resistor. First time the changes are bigger, with time the curve level out.
PS: A short sidestep to the K501 .... a bit fewer bass, but very musically - woman voices a short minor base. The K501 is a very good headphone with slim, neutral sound.
PPS: Some people would say - hearing before 400 hours burning in is damn - I would say .... looks like a wine-grower .... savour at each time of ripening process .....