If DTSMA decoding/bitstreaming is at the core of this premise, then I don't think "audiophile" is the right term to use here. The (true) "audiophile" is going to be concerned about music reproduction on a dedicated music format (SACD/DVD-A, for example). That is where the utmost attention is invested in recording/mastering to produce content that really can challenge "audiophile" standards.
Though movie soundtracks can sound "good", rarely are they considered "audiophile grade" to the same level that is present in a well mastered musical recording (regardless of lossless compression or not). It's a different standard of quality, and it has been that way for some time. Just listen to the music they play at the closing credits of a movie and compare that to the literal version offered on CD, and it should be fairly obvious that even the CD runs circles around it.
What does all of this mean?...simply that the presence of an operational DTSMA on the ps3 is not a particularly definitive basis to determine "audiophile grade" status, until a wide library of music content arrives in this DTSMA format. Until then, movie soundtracks in DTSMA are simply movie soundtracks in DTSMA, and not much more. Why do I say a "wide" library?...because if there are only 1 or 2 actual music titles you can play on it in that format, then what good is it really, whether or not it is "audiophile" grade?
The only real way to evaluate (at this time) ps3 for "audiophile status" (not that I put much credence in such a classification, anyway) would be to evaluate how it performs on CD or SACD content in either analog output or pcm out.
If you wish to test it via bitstream on a lossless codec, then you would only be testing the ps3 as a transport, anyway (which should be fairly trivial to achieve properly). The "audiophile-ness" of the sound would then be more a reflection of the decoding and d/a in whatever receiver/amp you have connected to the ps3.
That said, I don't want to give the impression that ps3 is not a very good player. I would not be surprised if it scored very high on a technical measurement level. Audio output quality would still need to contend with the impacts of fan noise (ambient noise contribution) and 3-prong AC connection (potential for line level interference), in striving for that "audiophile" crown, though. It's still going to be capable of audio output far exceeding in quality relative to what most people will connect to it in amps and speakers.
As to if "audiophiles" consider it a serious blu-ray player, why would "audiophiles" care about blu-ray players, in the first place? That is not their domain, anyway. "Audiophiles" care about music players, not video players. The ps3 may very well be as "serious" a blu-ray player as any other standalone blu-ray player, as far as playing blu-ray movies is concerned.