There
shouldn't be an audible difference between PCM or the HD audio formats because they are exactly the same.
Operative word being "shouldn't". A couple of persons that I respect a lot say that bitstreaming will help with digital clocking and jitter management. I curiously brought that up at AVS, and the one interesting reply I received was that (as you say) this
shouldn't happen, but it sometimes does due to less-than-perfect HDCP/HDMI implementation in the receiver. Or something like that. Who knows.
I don't care, I don't know, and I don't have any choice in the matter.
You're right about the secondary tracks. I still have yet to watch one though. Friends tell me I should really check out the doc on Surf's Up, a movie I've seen twice now, but I just get so bored by the extras and still can't be bothered.