I might pick up a pair to compare them to my HD650s. If they sound almost the same, they will be a freaking _steal_. If they sound good but can't match up, they'll still be a pretty good value. I have no illusions that I'll be selling my HD650s in favor of the HD6XX but in the spirit of comparison and spare cash, I might as well give it a shot! I'm sure I'll have no problem selling the HD6XX if I don't want to keep them.