The RKV's, in my opinion, are a terrific amp (as long as you get it used) offering mucho amounts of power. They're a headamp more for the "music lover" versus the "audiophile". You'll say things like, "I don't care if this ain't neautral, it sounds so damn nice!" It'll allow you to just relax and enjoy.
The new ones, from the importer that quoted to price to me, is uber expensive. Like three times the original's price. Like, 3 to 4 grand range. For that kind of money, you can definitely do better. Too many choices. But used, at a reasonable cost, well worth it!
Unfortunately, I don't have an Impedanzer for mine, but luckily ran across the EC/DC from Eddie Current, which seems to work similarily well. The only thing is, with the one from AV, you could hook up the K1000 directly to the back. On mine, I've wired my K1000's into a regular jack and am driving them from the amp, alone. Still sounds very nice.
The new silver one is quite pretty; however, I think I still prefer the old black 'n gold models. I've got a few amps, and if I had to let them go one by one, the RKV would be the last to go.