On DVDEXPRESS.COM you can purchase 2 different Apollo 13 DVDs. The first is a DTS DVD and under the description it reads that it will play DTS DD 5.1 and DD. The second is a standard DVD and under the description it reads that it will play DD 5.1. I assume that DD 5.1 is different than DD.

There does not seem to be very many DTS DVDs out there and some say this is a dying format-others that it's just beginning. I ASSUME that if you purchase the DTS DVD and play it on a non-DTS system (under DD) you will not get the same sound quality as if you purchased a DD 5.1 DVD.

I hate to have to replace my DTS DVDs if this format dies (if I want a better sound). On the other hand DTS, based upon what I have read, is more dynamic than DD 5.1. Persumably the only way this format will survive is through support. You will also face the same problem if you are going to be playing this your DTS on other systems which don't support DTS. My final conclusion is I guess it boils down to your use and comfort zone.