What I've noticed with my H3-2D is that it has some twitching with the yaw axis (which is the third axis in the gimbal). Otherwise the footage shot with 2D is very well stabilized. The 3rd axis in 3D removes this twitching (or what ever you want to call it).
In H3-3D you cant control the yaw axis with remote, like you can control the tilt (as far as I know). So the only use for the third axis is to dampen the yaw movement. So if you turn right or left, the movement will be slightly smoother and if your Phantom makes any random movements to left or to the right because of wind or any other reason... the third motor will take that out of your footage.
Personally I'm satisfied with 2D, as I can make my footage smoother with Warp Stabilizer (Adobe). Unwanted yaw movement with 2D is minimal in my opinion, so even the Warp Stabilizer doesnt have to do much work to get it fixed.
If I would be buying my gimbal/quad and 3D would be available... I would be considering only these two things... 1. Added weight ( I believe its minimal, but if its not... 2. Price).
I havent had my Phantom & Zenmuse H3-2D for too many weeks... and I would had not waited for 3D if I would had known that its going to be released soon.
As a recap
-If you want to have best possible footage out of the camera, all the time, every time... then 3D is worth the wait. It does not make your footage perfect, but removes (not always) the need for post stabilization. Although theres always use for post stabilization, even with 3 axis gimbals (in my opinion).
