The Microsoft HD DVD team now has a public blog.
Please note that the first entry links to some beta software that includes an iHD simulator.
Now, iHD is one of the major differences between the two formats. iHD is not technically a Microsoft-only thing, but it's pretty darned close.
What does Blu-ray use? Java.
And what codec is used in all currently shipping HD DVD titles?
What codec is likely going to be used in Blu-ray titles? That'd be H.264, which was developed by Apple.
So, it's [once again] basically a Microsoft vs. Apple/Sun kind of thing. Weird.
Me, I don't have the budget for high-def DVD players of any kind [and no real desire to see any movie currently shipping on HD], so I'm not going anywhere for a while. It's going to be interesting, though: on my dual core XP box, H.264 videos are fairly choppy [cf. the Drawing Restraint 9 720p trailer], but VC-1 trailers look awesome [cf. the Titanic outtakes from Microsoft]. Of course, this may have something to do with QuickTime's inherent quality under Windows; I bet it looks great on a MacBook Pro, for example.