So I now own both the Japanese pressing (PSCN-5049) and the American pressing, and can compare the sound quality side-by-side.
After A/B'ing a few tracks, my first impression was that the American pressing sounded better - more "full" somehow. After listening more critically, I figured out why.
It turns out that on the Japanese pressing, the volume in the left channel is much higher than in the right. This is the case on every track. On the American pressing, the balance is correct.
Below is a waveform from both pressing of "In a Snow-Bound Land," which illustrates the balance issue clearly on the Japanese version. When actually listening to the music, it's pretty noticeable - especially on headphones. In comparison, the American version sounds great.
This being the case: while the Japanese version is a nice collector's item, the American version clearly wins out on sound quality.
