I own the 840, not the 940. I love my 840's the sound is very natural, very alive, and energetic, almost perfect reproduction. They are built very well, and holding them you feel that build quality, and they can easily be powered from my ipod or android. I cannot ask for more from a closed circumaural headphone. Plus these dont sound like a closed headphone, they sound more open, however they block outside noise, and dont allow the music to leak.
I cannot comment on the 940's but I highly recommend the 840's.