So, it is true that uncompressed 5.1 is the better choice?
The answer is partially in the question
"uncompressed". Please don't forget that no matter what codec you are choosing for a DVD, Dolby Digital, DTS, DTS high biterate, they are ALL compressed AND lossy. Of course, if you have room on the disc, you can compress as low as possible, but there are still bite-rate limitations with those codecs:
Dolby Digital: 640kbit/s
DTS: 768kbits/s I think
DTS full rate: 1,5Mb/s
And they are lossy, so I guess that even if you compress as low as possible, you may still lose something. No need to say that when it becomes a bit richer, you will surely loose something with those codecs.
Then comes the HD codecs:
Dolby Digital Plus 6 mb/s (lossy, but already 4 times what the best DVD codec can offer)
DTS HD up to 6 mb/s (lossless? I'm not sure)
Dolby True HD 18 mb/s (lossless) (give me some!)
DTS Master Audio up to 24 mb/s (lossless) (oh yes, hit me!!!)
uncompressed PCM up to 40 mb/s in theory (lossless)
DTS HD, MA and DD TrueHD are lossless tracks which are just compressed without any loss (see it as a "zipped" soundtrackof a wav files, when Dolby Digital or DTS are a MP3).
Then there is the number of tracks, the frequency, I don't know all the details. DTS Master Audio is said to be the top, but as long as you choose a track between those 3: DTS MA, DD TrueHD and PCM uncompressed, you should have a soundtrack quite close to the original mixing of the movie. Providing your speakers can reproduce everything of course, and that the source is good of course