Pros: Quiet, Inexpensive, Musical Fidelity Quality, Solid Enclosure but Easy to Tube Roll
Cons: No Longer Available New
I'm going to start by disagreeing with the two previous reviews.
You DO NOT need to tube roll this amp. The original Jan Philips 6922 are considered a premium version of the 6DJ8. With the Sennheiser HD-600/HD-650s, you get what I'd call a more mild tube sound. It's detailed enough to hear the page turns and periodic shuffling during some symphonic/chamber performance. It's smooth, but not excessively, and has the punch you'd get with an SS amp. Of course, you're probably buying this used at this point, so you may want to swap warn tubes for that reason alone; but there's no need to go nuts and buy break-your-budget NOS replacements -- feel free to just replace with the stock JP 6922s.
That said, I purchased a set of Amperex 7308s as recommended by the first reviewer. And boy do they sound amazing! Extremely smooth and detailed. They cost in the high $100s, so they are near the value of the amp. But boy!
In terms of comparison to modern amps, I don't have anything to refer to. But the quality of the V3 is absolutely supreme, and you really aren't going to go wrong by any means in terms of "bang for buck." Especially in the current used market. You also get a solid case that completely encloses the internals including the tubes, so you don't have to worry about little ones accidentally touching them.
I love the company name "Musical Fidelity," because that really describes what you hear with this amp.