I have flown the LHR-PVG quite a few times always at the back in Economy but its not bad. Its an A340-600 and I have had some great trips with VS. The views at Pudong are quite good-expect to see an amazing range of Chinese airliners plus the usual heavies from USA (including freighters) and some interesting a/c from Asia (KAL A330). Mostly western types though. Be careful if you want to spot using bins-take a small pair and try not to be too obtrusive.
A word of caution. If you are taking the Maglev train into the city, before you embark get someone to write down the name of your hotel in Mandarin for giving to the taxi driver- this saves time as some drivers have ripped off UK tourists by taking them way off of their route. I have also used the taxi’s from the airport and have again got my hotel name translated into Mandarin.
Hotels are fabulous as is Shanghai itself. I stayed at both the Hilton and the Holiday Inn (by the main railway station).
Finally; the flight back is fantastic during the day with plenty of scenery to look at from 35,000 feet. The duty free shopping at PVG is not that extensive so make sure you buy your pressies from the city.
Have a great trip.