The latter, I prefer Dolby's ambiance extraction/channel expansion to DTS's. That is to say, I like the way Prologic sounds more than Neo:6.

So if I have a DVD or BD with a DTS 5.1 soundtrack I'll pick it for playback, but processed with PLIIx to make it 7.1, rather than Neo:6.

Pioneer PDP-5020FD, Marantz SR6011
Axiom M5HP, VP160HP, QS8
Sony PS4, surround backs
-Chris