If ORBX did do some work for DCS I would be first in line. As much as I like the former, I often jump over to DCS because the flying experience in my opinion is superb. Glassy smooth with no stutters, well optimized (as of the latest update), and just a pure joy to fly. Apparently they are going to release a new map for free which is very close to release since the latest "Viper" F-16 is pending and most of the video is from a different map all together.
I would also venture to say the code in DCS is superior to P3D. eg: GPU use is more optimized than any other sim I have flown. Of course, having said this, AI is still a FPS killer like all the rest.