Pulled up this graph on headphone.com.. Not entirely sure what I'm looking at though.
I'm a bit leery of the auto adjusting head band on the AKG's. I do like that they have removable cables though. For sure I'd go with the 840 pads if I went with the 440's. Watched a few video reviews for the 440 and they look giant lol. Do they still fold with the upgraded ear pads?