Thanks for the honest impressions. The difference to the A829 is smaller at the beginning for sure, but as the digital amp burns in, it definitely opens up the sound even more, so that the differences you noted become more obvious. Especially soundstage, that really opens up. For those of us who bought it mainly hoping for the jump in audio (myself included) it has proven to be very satisfying after some more play time.
Direct comparisons with the Zune HD will definitely be interesting. I look forward to that.. but from what I've read, I don't see anything about improved SQ over current models, except in the HD radio feature. Correct me if I'm wrong....