Burn-in time: it's no joke.

[theaudiohobby]

I would further argue that after 300 hours of listening, you have simply become accoustomed to your specific sound system, and may be more in tune with how the sound is reproduced on your system.

And, there certainly might be a difference in sound between a CD and SACD, but it ain't because the player is "broken in".

Amen