I just finished my set about an hour ago. I'll post my general comments in the review thread. After the little glitches on disc 2 in the Hiro ep, I had another brief stutter freeze on disc 3 that corrected itself. After that, no issues for the rest of the set.
Watched the first broadcast ep. and about half of the unaired pilot this evening on my 720p front projector. The quality was outstanding. You could practically climb into shot after shot, they were so dimensional. The HD DVD version is definitely the one to have regardless of the premium price.
I cracked open my HEROES HD DVD box this weekend to catch up on some key episodes before tonight's Season 2 premiere and I had issues with getting some discs to play on my Toshiba HD-A1.
DISC 3 - Would load up and play the Universal HD DVD logo, but then freeze on a black screen before going to the menu. It did this three times and then it suddenly worked and went to episode one... but only after I hit the PLAY key. The only way to get the main menu to appear was to hit ENTER during the first episodes playback.
DISC 4 - Wouldn't spin up at all for 2-3 times. Just kept getting the NO DISC error with the disc in the tray. Finally it worked, but it sure was irritating.
Don, sounds like some defective disks. EVERY disk I have seems to kick my A-1 into slow mo mode and a simple pause and rewind 3 seconds then hit play gets it out of this. I'm on the record on how much I think the A-1 sucks and these issues appear to be deck related and not software, as they can happen once and then not again replaying the same sequence a dozen times. I've NEVER had hard lockups that are repeatable like you describe tho, so I would go for a disk swap to start.
I too have had various issues with my A1 locking up for unknown reasons but your problems do sound disc related. You may consider taking them upto a Best Buy Magnolia or Circuit City store and seeing if they'll play in their A2 models. I've did that once to validate whether the problem was the A1 or the disc. In my case it turned out to be the disc.