I have one and am thrilled with it. I have listened to it with various Grados (SR-60 / 80 / 225 / RS-2 / RS-1) as well as a few Sennheiser phones and love what it does. I did find that a huge upgrade could be had by replacing the 6922s with better tubes (stock is by no means, bad, JAN Philips iirc, they'll last forever, but I preferred the mullards). Tons of control over even the hardest to drive phones, great bass, holographic highs, and a whole lot less fatigue even with some of the brighter cheap Grados than I've ever had. The construction is top-notch, really a quality piece, all of the new small x-series stuff is gorgeous!