The analogy I've heard is that you need to spend 20k to better them
4est, I'm not sure I'm in as complete agreement with you on this. I have a BOLDER digital modified SB3 that I've been using for over a year with a good linear supply (but not the super-duper BOLDER PS). I also have a Proceed PDT3 transport and heavily modified EAD DSP7000 Mk.III DAC. I've heard newer players and DACs in my system, and feel comfortable in saying that I haven't heard anything yet in the under $4-5K category that makes my transport+DAC sound like crap.
The SB3 as a digital source sounds very, very good, but not as good as my transport feeding the same DAC. In terms of tonality, speed, and dynamics it's all but a toss up. But the SB3 produces a significantly less deep and wide soundstage. Easily heard by most listeners. A friend who had never heard my system before picked it out in less than 15 seconds of playing the same tune on the SB3 after having heard it on disc via the PDT3. I'm not suggesting the SB3 sounds bad, far from it. But the transport does produce a better musical soundscape.
I'm making an extreme sounding point to tell you that (at least in my system) there are differences, even if they are actually smaller in an absolute sense. Would I give up my SB3? Absolutely not. Would I give up my transport? Not just yet.
I have asked if this could be a cable interface problem from the SB3 to the DAC (you know, jitter and whatnot). Some think that may be effecting the soundstaging, so I'm willing to experiment. The transport is connected via AT&T glass.