Pros and Cos for NTR experienced SFO (>3500hrs factored) for EZ (UK/contient) and EZ Switzerland ?
Also it does not seem possible to apply for both at the same time... (applications mutually exclusive.... i.e. warning of rejection if both applications are filled at the same time... ) which seem strange as they are two different entities....

Easy choice, just apply depending on where you want to be based, because the transfer between the two is not so straightforward.
In Switzerland salaries might be slightly higher, but so is cost of life.
Personally I would not be thrilled to live in Geneva, no matter how much money they offer but hey, everybody is different.