I have the posibility to upgrade from C to F on the ZRH - GRU flight on Thursday, but is wandering if it is worht it considerng 1. it is the old F class 2. it is a night flight etd @ 22.30. One point to consider though, is that I have 2 hours in ZRH prior ton departure, thus taking advantace of First Class lounge. I am star alliance gold, so have access to Senator Lounge, but have not flown F before, so do not know the difference?

Optimally I would have upgraded on the return leg on September 21st as this is an evening flight, however not availble online.

Your replies are greatfully appriciated...