I got HD 650 drivers for an extra HD 580 parts pile I had! I haven't gotten to use them as I'm on vacation, but I will be comparing with my HD 600 and Modi/Vali stack. I'm so excited and may just keep both since my "HD 650" cost me roughly $120. I really don't know how these could be "better" than the HD 600. Although some people say the HE-300 sounds like a poor man's HD 650, and I love my HE-300. Can't wait to get home on Thursday!