I can only comment on FS Shanghai as I spent 3 nights there last year. Although there is nothing terribly wrong with this property, there is nothing great to rave either. I got a 1 bedroom suite and while it's nice, the decor is as bland as it can be. Bed very comfortable, working area has US outlets and the bathroom has a separate shower stall with a L'Occitane toilettries.
The pool is a pitiful little thing and the spa is simply not appealing.
Breakfast in the ground floor is not bad, but it did not leave any impressions on me whatsoever.
Location is good, although I'd like to think that Westin's location is excellent.