Well, audiophile is kind of a loaded word.
I tend to think it applies to people who are more into great sound than great music. Although many audiophiles are definitely into both.
True “audiophilia” translates into home stereo systems worth thousands of dollars to achieve the higest fidelity playback possible.
Here’s the deal: even over a $50,000 home stereo system, an MP3 won’t sound good. It has a sampling rate a fraction of CD’s and some people don’t even believe the sampling rate on a CD is adequate – hence, the market for SACD (Super Audio CD) and the fact that many high-end home systems still contain a turntable (a purely analog signal).
That’s why I say none of these players are “audiophile”. They can’t be because of the SOURCE – a digital signal compressed from a previoiusly compressed signal.
As to the quality differences within the different players – well, digital playback is an easy thing to do well. We’re not talking about great levels of amplifying, so I have a hard time imagining there are noticeable differences in players.
Of all audio components, the CD player probably has the least variation between the very high end and the very low end.
And though I don’t know this for a fact, it stands to reason that a purely digital playback device is going to have even less variation. At least in a CD player there is room for mechanical improvements.