BTW, what is it that makes the Arca-Swiss system attract such devoted fervor when compared to the Manfrotto 234RC Monopod head & RC2?
Am I missing something? Or is it a treatable case of FOMO (Fear Of Missing Out)
One thing is that you can slide the foot back and forth in clamp to get the balance right.
OK. I'll give a quick and probably incomplete list of reasons:
1) As Jim said, adjustable balance on the fly.
2) Plates are more comfortable to hold on the lens collar and less obtrusive on the camera while being non-rotational.
3) Quieter to engage/disengage.
4) Strong as a vice (because it is a vice).
5) Non-proprietary. There are ballheads out there other than Manfrotto's. I tend to favor Markins and Acratech, while many here like the Really Right Stuff models. Oh yea, I hear there's even a company called Arca-Swiss that makes some really nice heads
The point is interchangeability. Hope this helps.