Meanwhile I reached the same conclusion. Plays the Matrix fine from folder, but... stutters with 1080/24. Works only correctly with 1080/60. This is a showstopper.
I noticed the 640kBit display on the TruHD track, but I believe (hope?) this is just an error in the display. At least 24bit samples reach the soundcard, which is nice (PowerDVD 7.3 downsamples to 16 bit, but I can live with this - if I have to).
Despite my first belief, it does *not* work correctly with ReClock. It stutters and crashes after a while. Too much anti hacking code inside?
Anyway, I agree, it is unusable at this moment.
So, this leaves PowerDVD 7.3 as the only usable HD player (Don't have PowerDVD 8, and don't intend to upgrade soon). What a shame. I have to live with its shortcomings (no playback from folder, audio downsampling).