My little input.
I see the point on the structure being completely closed and thus better protected in the field than most geared heads.
The RC4 works well for me. The most load I use is my Sigma 500mm f4.5 with a DSLR, about 4.5 kg, it works fine. I do not use the Quick Set with the heavy load it gives the same issue as a ballhead, it flips over.
Other points I read where people saw possible improvements:
- movement between the quick release plate base, plate and the camera, there is some, but not a lot. True the RC3, plate with screw seems to be my preference with less movement.
- adjustment of one direction moves the other direction. It seems to me that it does, I do not have a problem with it, adjusting works quickly for me.
- 30 degrees is quite a lot and if you really need more reverse the plate on the camera/lens.
- it is big and heavy, it is. When I can I use it though, since the precision is a joy to work with. On longer hikes the ballhead will have to do.
It is difficult to explain the precision of geared heads though, I guess you have to use it to really understand. It is very much like macro rails, maybe a bit faster in thread.
So I do not regret to have a Manfrotto 405, it is more then I need and is not very portable, but there is no fiddeling, it feels secure and works like a breeze.