Upon first hearing it, I was so impressed with the X4 / Don Sachs Vahalla integrated amp combo I knew then and there I had to have a pair of Spatial speakers and then went home and emailed Don to put in an order for a Valhalla. I ended up going with the X5s, as I liked the active sub and the possibilities for even lower wattage amplification it allowed, but I still have my order in with Don and would buy one tomorrow if the opportunity presented itself. It really is a fantastic combination. I played a generous swath of musical genres through it (seriously, from Macklemore to Mozart), and it rendered them all both impressively and, more importantly, musically. The only issue with Don's gear is he builds it himself and that takes time. But, if you aren't in a rush and have something to hold you over in the interim, I can't recommend this combination highly enough. Good luck!