I agree with some of the descriptions of the K702, especially tdockweiler's opinion. I found the K702 to put instruments too far apart. It was almost unrealistic sounding at times. The HD600 just sounds more natural. It is much more "musical". The only time I did prefer the K702 maybe equal, or slightly over the HD600 was in a couple instrumental songs that consisted of more instruments than the average song contains. The spaciousness and detail made for an interesting experience. I did find the bass in a couple songs to hit very low with the K702, then with other songs it just wasn't there. Directly going from the K702 to the HD600, it was night and day difference in favor of the HD600, with all rock,metal, pop, techno. The HD600 not only has more bass quantity, but a much more concentrated and involving sound, which allows you to really get into the music. The K702 is just too far detached. Things can sound "thin", even though it was properly amped. I would not say the K702 presents more detail than the HD600, it just presents the detail in a slightly different way. I found the K702 highs to be more fatiguing than the HD600.
At first I thought I'd prefer all classical on the K702, but directly comparing I found the HD600 to actually sound more realistic. IMO, piano and violins sounds are more realistic on the HD600 vs the K702. I prefer the HD600 for basically all classical.
After adjusting the headband on the HD600, I found it to be extremely comfortable, more so than the K702. The K702s seems to be too loose at times, and I'm not a huge fan of the automatic headband adjustment system. Over time, I have a feeling the stretch adjustment cords on the K702 will lose some of their strength and the headphones become looser.
One thing I'd like to mention, is that I experienced no sort of "veil" with the HD600. I actually found them to be slightly more forward than the K702 for vocal, and of course everything else sounds more forward and involving on the HD600 due to not having the characteristics the K702 has. The HD600 just sounds amazing overall, such a great all-around headphone. It's great when you find the sound you are looking for. I was a fan of the HD555/595 before and enjoyed their sound; they are good in their respectable price range, but overall can not touch the HD600s. It seems the HD600 has all I need, for now.. lol.