I have been lucky enough to fly ‘F’ class with Swiss on several occassions. I have flown to Hong Kong not Shanghai but I imagine the service will be similar.
The seats in ‘F’ are very comfortable fully flat beds with nice large pillows and a proper duvey when you are ready to sleep. The crew will make up the bed for you if you ask them to. The food was excellent both ways with an excellent choice of Western and Chinese dishes and the service was really good, cabin crew attentive and available but not in your face. The in flight entertainment was not as good as some other carriers on the route but was more than adequate and I was not bored on either flight.
I am sure you will enjoy the flight and would be interested to hear your views when you get back as I have not flown with Swiss for a while. Bon Voyage!!!