DTS is a competitor of Dolby Digital that supports higher bitrates (thus less "loss" in the "lossy" compression). Most people tend to prefer DTS to Dolby Digital, although there are some who argue that it's difficult to perform a fair evaluation of the two because the two versions are often mixed somewhat differently and because DTS generally adds roughly 4dB of gain (making it slightly louder than Dolby Digital, something that is often perceived as sounding "better" to the human ear/brain team). I'll often pick DTS if it's available, although I often find the differences between the two to be subtle.