My X-5s are my 3rd set of Spatial Audio amps - I am a true believer. But the search for the perfect amp continues (aided with advice from fellow audionerds here on the circle). I have owned an LTA ZOTL10 and currently use an Ultralinear +. I just purchased a Kootenay, as it is one of the 2 amps getting a lot of good buzz. In correspondence with Don Sachs yesterday, he said he was making no more Kootenay amps, but was concentrating on a new pair of 300B monoblocks (very spendy - $12-15K). Whether the Valhalla integrated is still being made I do not know. Now to spend a few weeks comparing the Kootenay to my LTA Ultralinear+. I really like the Kootenay a lot - like turning on a technicolor switch. Maybe if I convert my house to a duplex I can afford a pair of his new amps.