One of my pet peeves about new formats is that the industry doesn't seem to have learned from its past. I'd hope that we wouldn't repeat old mistakes, but sometimes, well... that just isn't the way it seems to work.
Case in point: currrently, I know many folks who have been trying out Blu-ray authoring using Toast 9 or Toast 10. It's a great way to get started, as it doesn't require a large investment in a Blu-ray burner or Blu-ray media to begin experimenting with high-definition optical disc creation.
But sometimes the best laid plans go astray, especially if the player manufacturers somehow happens to upgrade firmware to fix something, and accidentally winds up breaking something, like, say, BD on DVD-R playback capability.