I had trouble with versions after 2.6 until I tried 2.7.2 Epsilon WOW the twitches are gone!
Even with the default PIDs (apm2, ublox, quad), the flight was super smooth. I increased Alt Hold P to 0.8 and thrust rate P to 0.6 because the default settings let the copter sink when I activated alt hold, but these adjustments fixed that. Now the hold is very responsive and tracks the terrain perfectly.
I really liked 2.6 and had many successful missions with it. I thought the next version would have only minor differences, but I was wrong Jason and his team have significantly improved it!
For example, here’s a little 6-waypoint mission run several times under 2.6
It hits all the waypoints and stays pretty close to the path. I thought improving this would be not easy, but now, running the same mission with 2.7.2 Epsilon
Now it turns sharply and is incredible to watch it feels like a robot with a real mission. The landing accuracy is almost uncanny. Seeing it fly at night with the LEDs streaking across the sky is exhilarating.