I'm waiting on a set of these, I'll most definitely do a lot of tweaking. I have both 650's and 800s to compare to, as well as the PC-166s, which are a fine pair of headphones. Being stuck in a loud barracks (full of idiotic AIT students), I am looking forward to the sound isolation. I intend to experiment with both driving them from the PC-166's USB key and also from my Total Bithead. We'll see how it all goes, but i have to wait for Christmas Exodus for any of this fun to begin. I'll keep you posted!