Once again, folks do not read the posts. Excerpts from the above link:
Let's begin by looking at how uncompressed audio works. A PCM track is an uncompressed digital format that is 100% bit-for-bit identical to the studio master.
On the other hand, Dolby TrueHD and DTS-HD Master Audio are "lossless" compression formats. Although they're compressed to take up less disc space than a PCM track, once decoded they're also bit-for-bit identical to the studio master.
Standard Dolby Digital, DTS, and (to a lesser extent) Dolby Digital Plus and DTS-HD High Resolution are all "lossy" compression formats. In the above scenario, they'd not only drop the 0s, but also drop some of the 1s that are deemed less critical to human hearing, under the belief that most people won't be able to hear the difference. The higher the bit rate, the less data is dropped. DD+ and DTS-HD HR are not only higher bit rate than old DD and DTS, but also more efficient at maintaining more of the data at lower bit rates. Still, they're not a perfect replication of the studio master the way that the PCM or TrueHD and Master Audio formats are.
PCM is not needed unless you don't want to decode within the player and have the space and bandwith to push the uncompressed sound track which BD has plenty of both. While HD-DVD uses DD+ primarily and this is better then either DD or DTS it still is not an exact replica of the movie sound track. As for which format uses what, it is the soundtrack and how well it is done that will provide the end results that you would enjoy.
If it does not bother HD-DVD folks to not have the best audio possible why should it bother any BluRay supporter? I don't care if HD-DVD doesn't have the ablility to support a lossless audio track (for whatever reason)-- I support the format that is capable and does support multiple lossless audio tracks on one disc -- BluRay.