I picked up this player today. I must say that I am astonished at how good it sounds. I have not heard much good audio equipment in my life, but this player thouroughly creams every CDP in my experience. I bought the player for 179 at Circuit City (couldn't be bothered to wait on mail order

) and bought the Kind Of Blue SACD while I was there because I had the redbook Kind Of Blue to compare it with.
I took the unit home and set it up with my JVC DVD player, my current standard for redbook playback. It is a good player, or so I thought. I ran the signal from the JVC DVD player with Monster Cable 100 IC's into my JMT built Cmoy powered by a 9v replacement wall-wart from Radio Shack and listened to the opening track of Kind Of Blue, So What, through my Sony MDR-V6's to establish a baseline.
The sound was what I expected it to be, warm and closed in with the standard V6 round over present bottom end and peaky treble. It sounds like listening to the players playing in a small closet. VERY intimate.
After the track was done, I switched the IC's and put them in the outs of the SACD player. I took the Kind Of Blue redbook CD and placed it in the Sony unit. All else was the same. I played So What again.
The soundstage was the most noticeable change at first. Where the sound was quite narrow before, the sound picture very noticeably relaxed, feeling much less congested. The bottom end was less rounded and full, much more natural, and I could now hear room ambience and other clues that were inaudible from the very warm DVD player. The sound cooled significantly, the listening experience was much more relaxed and natural overall.
After So What was done, I then replaced the redbook Kind Of Blue with the SACD Kind Of Blue. All else remained the same. I played So What on the SACD, and more improvements were yielded, though not as dramatic as the switch from JVC redbook and Sony redbook. Now, the instruments took their place in the sound picture in a much different way. Where the redbook side recognized little difference in the SPL between instruments, the SACD really put the instruments on different levels, Miles, Coltrane and Cannonball being front and center (or front and side

) with the piano, drums and bass much farther in the back, clearly in a supporting role. It was easier to hear the details on the cymbals with the redbook playback on the Sony player, but more gentle tapping of the SACD playback seemed more natural. Soundstage again improved, making the V6's almost sound relaxed

.
I then placed a few of my favorite redbook CD's in to take real world test of the kind of music I usually listen to. I listened to Melvins' Houdini, Live's Throwing Copper, 10,000 Maniacs Our Time In Eden, and Tool's Lateralus.
Melvins is a really nasty sounding recording, and I was reveling in the filth that the Sony player was quite faithfully reproducing. Where the distortion and noise of the guitars actually has some coherence with a warmer and less detailed player, the Sony player reproduces a chaotic, insane mishmash of ugly sounding guitar and pounding, overwhelming and loose sounding drums. Awesome!
Live's Throwing Copper revealed much more detail than I ever heard in this band before. Their drummer is quite an accomplished percussionist, and I could hear his cymbal work and more subtle differences in the strength of his hitting various drums, making for a more meaningful and immersive experience. It is here however that an initial complaint about the Sony unit comes up. Out of the box, it is a rather harsh player, especially for rock. A sustained cymbal attack can sound quite unpleasant, not that the unit is not reproducing the sounds faithfully, but is over sharpening the high end, made even worse by the peaky V6's. The upper harmonics of a distorted guitar basically get the same treatment.
With 10,000 Maniacs Our Time In Eden, the same sharpness issue exists. I listened to part of this album with my Franken50's, the drivers from a Koss KSC-50 implanted into the housing of a Sony MDR-301 with a few bits of foam padding for reflection reduction and comfort. Usually this headphone sounds more relaxed and rolled off treble wise than the V6, but with this Sony player it had much of the harsh sibilance in Natalie Merchant's vocals as the V6. Overall though, the soundstage was again much more relaxed and natural, and the timbre of the drums, horns, and other instruments was much more individual and recognizable.
It is with the Tool CD, Lateralus, that I really began to tire of the Sony player. In the quieter, subtler passages, it was great to be able to clearly hear the hissing of the guitar players tube amp, and much of the small details of the bass were audible now. But during the cresendos, with the drumer smashing cymbals, the whole presentation became painful, and ultimately unlistenable.
Bear in mind that all these observations are made with the player right out of the box, with ZERO burn in time, and listening to its output on a Sony MDR-V6, which is well known as the kings of peaky treble. With a few hundred hours of burn in and/or a more neutral headphone, this Sony player stands head and shoulders above virtually all competition in price/performance.
If you are looking for a budget redbook player or an inexpensive introduction to SACD, I cannot imagine any player giving the Sony DVP-500V serious competition at this price point.