Pros: Sabre detail without the harshness, full customizable to suit your individual system
Cons: original $750 version no longer made, new version better but a bit more expensive
There's really no point in me writing a review, as I concur with the more professional reviews written below. A huge range of people have spent hundreds of hours combined with this dac, and found it to best significantly more expensive items like the Anedio and Metric Halo. Obviously, your mileage may vary, but the knockdown giant-killer feature of this dac is, for me, the customizablity that no other top-level dac offers. For those who say that tubes are simply not as good as solid state or discrete, let me simply remind readers that the Level 4 Lampizator and the Killer Dac, both $4000+ dacs widely regarded as the absolute best, money no object dacs, both use tubes. 'nuff said.
But the point is, you don't have to use the tube. You can modify the sound to suit a dark setup, a light setup, and anything in between - and better, you can switch as your system changes without having to sell everything off.
I a-b'd this against a wide range of dacs in its price range, and came away convinced that - even stock - this beat them all. Modified, it beats them all well and away. They're built like tanks - think classic McIntosh equipment - so will likely last many, many years. Grab a used one while you can.