mikefungIt's good. I had the 612 pros, but returned them when I heard about this. I have the E10k and they're amazing; they can drive these really well.
mikefungAlso, the 7XX has a detachable cable. This is excellent if you want to replace the cable or use a shorter one. I ordered an Amazon cable that is ideal for me when I want to listen to my headphones on my bed or somewhere not at my computer.