Re: DTS or Dolby Digital?
IIRC Spielberg has a stake in DTS, hence some movies ONLY being released with a DTS soundtrack. DTS was not originally part of the DVD spec, but Spielberg fought to make it so. (e.g. I have a 1st generation player, Panasonic A-300, that does not decode DTS.)
I now have the ability to listen to either and I find more often than not I choose DTS, unless it was originally a 2 track that was remastered into a multi. (e.g. I watched the David Bowie - Glass Spider Tour DVD the other day and the DD soundtrack was better to my ears than the DTS)
Back in the day, the comparisons between the 2 showed that DTS was quite a bit louder than DD. Once the sound levels were adjusted, IIRC, it was difficult to tell the difference between the 2. (Note that this as 7-10 years ago) Can't say that I have done much, or any testing, myself.