I regularly fly a MPP and
M2P.
M2P is better, but I'm not sure it's worth the upgrade cost. I was expecting a much greater improvement in the image quality. Quietness seems about the same. Stability seems the same. Object avoidance is theoretically better (I hope not to test that).
If buying new I'd buy the
M2P. If I had a MPP and didn't need another then I'd likely stick with the MPP.
As to
SC. I use Litchi and Field Agent quite a bit (actually haven't used GO4 in many months) so it wouldn't work for me. I have an iPad mini that I use with the standard controller with a sun shield and I'm relatively happy with that. I'd love a brighter and less reflective display but I'd not want to be locked in to GO.