After reading through this entire thread and all of the reviews I could find, yesterday I ordered a new Fet Valve 600R. It will be used in a system where the primary source is a VPI Prime with a Hana ML cartridge feeding a Bob's Devices Sky 20 transformer to a Vision Q phono preamp. The Vision Q connects to a Rogue Audio RP-5 preamp. The speakers are Magneplanar 3.7i's that are crossed over at 35Hz to a pair of MartinLogan 1100X subwoofers. The 600R has some big shoes to fill - it will be replacing a Bryston 4B SST2 amp which I consider a fine amp, especially for Maggies. All of the information I could find about the Fet Valve 600R made it a pretty easy choice for me but, in truth, it is the reputation of AVA, and my direct dealings with Frank and others, that sealed the deal. There are few audio companies out there that offer the value that AVA does, and I can think of very, very few that have maintained a standard of excellence in the same league for such an extended period of time. I'm greatly looking forward to getting my 600R and will certainly report my impressions to this thread once I've had the opportunity to form them.