i've owned the a50 and found it to be one of the best amps i've ever owned, provided your loudspeakers are right for it. overall there are several classic class a designs from pass, music fidelity and sugden that i could say come close in overall presentation..detail, weight, balance, tone... and they sell for much less....i will say though, that the more conventional accuphase p450 held its own and more with the a50 and the mac 602(which was my favorite ss stereo amp of all time). the p450 and mac602 never met a pair of speakers they couldn't 'control'.