The bluescreen feature can not be found on the Blu-ray version of the film not because Warner favors HD-DVD over Blu-ray. Its because the current manditory specifications on Blu-ray players do not include the ability for picture-in-picture video. As reported earlier, The Blu-ray Disc Association has mandated that all players manufacturered after October 31st of this year must support BD Java, which will then support picture-in-picture capabilities. The HD-DVD equivalent to this standard is HDi and has been enabled on all HD-DVD players for some time.
Another feature pointing out the differences in the two formats is the fact that recent revisions of HD-DVD hardware allow it to be Internet ready to receive online content for specific movie titles. "300" on HD-DVD will take advantage of this online content and let viewers browse and purchase movie related items such as ringtones and wallpapers.
Its not all sad news for the Blu-ray version of the movie as it does have one thing the HD-DVD does not. That is an additional uncompressed audio Track encoded to Linear PCM 5.1. This is a Blu-ray exclusive encoding and takes advantage of the 20Gb difference in storage that Blu-ray has over HD-DVD.
Source:
Daily Tech