Well - I have owened both this year: 2004 Titan XE 4x4 CC & now a 2004 Ram 1500 4x4 QC 5.7 Hemi. I don't have actual track times, etc, so I'm going by the "seat of my pants" feeling. (1) I think the Titan is quicker off the line (2) I think the Ram Hemi has a stronger, quicker mid range 50-75 mph. A few people from a Hemi Ram site I visit that have raced against Titans seem to agree with this opinion. Of course there are people on both sides that claim their truck is the king of all trucks, blah, blah, blah. Like someone mentioned earlier, I think it depends on who's driving and how they're driving. Also, remember not every Ram is a Hemi either, and I believe the current 5.7 is rated higher than the previous 5.9 (working from memory on that one so don't hose me if I'm incorrect) According to Dodge, the Hemi accounts for about 30-35% of there Ram truck sales according to an article I read a few weeks ago.
I think both truck have their finer points and are fairly equally powered - my feeling from driving both is that they each exercise their power in different bands. My Titan always felt like it launched off the line - and my Hemi accelerates like a rocket when your cruising around 45 mph and slam it. Just my $.02