Have not had any problems downloading or playing back any file from HDTracks. As for all the commentary about recordings that just sound 'meh', well, they probably sounded meh before but our previous playback chain may not have noticed. In my youth I thought many albums were superb but I was all agog at the music itself and not the sound quality. Many rock recordings back in the day were simply atrocious but we are sentimentally attached to the memories of the time and hope to recapture a bit of former glory. The pieces from HDTracks I have been grabbing are of music that was recorded and mastered superbly (think Steely Dan) or is simply not available anymore unless one wants to spend mucho dinero on elusive LP's and what's left of the thinning herd of SACD's. Gave up LP's. 'Nuff said on that.
As for the mastering, I have noted here, and on other forums, that a good recording, well mastered, can sound just great on a 16/44.1 CD. Many little things have to happen in the chain for that to happen.
I've often wondered about the early days of the LP. Analog tape with hiss, mastering and cutting of the lacquer, pressing the LP's, ceramic cartridges, heavy tonearms, dubious record changers, tubed preamp/amps and mostly crap speakers. How would anyone know if it sounded good? That fact that it sounded at all was the thing. Like the dancing bear, it is not that the bear dances so well but that he dances at all!
Returning to HDTracks:
Jazz at the Pawnshop - worth it, no brainer - beautifully recorded, some of the tracks are brilliant, funny, mediocre, but so what? a moment in time
Diana Krall - Quiet Nights, Look of Love, Christmas Songs - Jazz people really care about their recordings. period. also it appears that they are minimally miked, and done with no over dubbing. Live in the studio
Donald Fagen - Kamakiriad - Clean, pristine
Fleetwood Mac - Rumours - Have the DVD-Audio as well - there are differences but they are subtle and are more a matter of taste. like wine. pinot or zin?
Eagles - Hotel California - See above
These are just examples. I really don't obsess over this stuff since it is the music that matters to me. If I don't feel like moving to it, or crying or grinning or singing along, the rest is unimportant!