Prae speed runs are roughly 25 minutes, as are CM assuming you have a good group. Since DF limits options, you should make your own out of a single tank, 2 healers (1 if your healer is really good) and the rest dps. This also works for CM if your dps don't mind dealing with adds during the boss fights, as you can effectively zerg bosses down much faster. On average that's how titan goes now, 2 healers 1 tank and 5 dps....sometimes a war operates as a 5th dps instead of tank when the group is competent.
The only downside to prae speed runs is ps3 users can't do it in 25 minutes, due to loading between cutscenes...oh and no one willingly taking ps3 players now, at least on ultros.