I live in Zurich and work all over the world in aviation IT. As part of my job I spend a lot of time flying mainly on SR, out of Zurich. All I can say is that in my experience SR flights are rarely on time departures, so if foreign carriers are receiving a worse situation then i pity them. I don not believe that this is the case, though, and that runway restrictions are mainly to blame in both GVA and ZRH. As far as preferential treatment on nationalistic basis goes, I am british and proud to be so, but having worked at LHR and LGW as well as many other UK stations, I have seen many instances of preferential service given to home carriers so, if this happens elsewhere, who are we to complain?