The P3D Q5 will have 215 lumen output and a bit more focused beam, the L2D Q5 will have 175 lumen output but better runtime by almost double. As was already mentioned, the battery life/cost issue is not stacked well in favor of the P3D.

Both are great lights. I use a L2D because I already have AA batteries and chargers and my commute is almost 3 hours round trip.