Runtime P3d vs Us
Hmmm, I haven't run either one down on a set of batteries yet, and I've owned and used both for 3 months plus so I couldn't tell you about one lasting longer.

The throw of the U2 is far and away better than the P3d. The big, "orange peeled" reflector sees to that. It is a compromise though, the U2 is a bit big for most pockets. I was super excited to get my hands on a Cree LED but I'll admit I'm underwhelmed. I was expecting 50% more light output than the U2, but that's not anywhere near the case. The P3D is a good light, but of the two I use the surefire far more. In fact my e2d with KL1 head sees more use than the P3d.