I prefer the HDE. The setup simply makes sense to me. If you have no experience it probably won't matter which. I have had a Raptor 50 for almost 2 years and the setup is the same on the HDE so it was easy. On the HDE 1 servo controls 1 function. On the CDE all 3 servos(pitch, roll, and elevator) work together to control the swash and in turn the rotor head.

From people who have flown both, most report that they fly the same when setup properly. I really like my HDE, and do not care for eCCPM.