It's really slight edge... that's why I alternate my stay between the FS and MO.

Plus for the MO:
1) Much smaller hotel than the FS - It's got that Boutique feel
2) A rich and proud history and Asian character to the hotel - and it shows in the room design and public spaces.. ie. the Asian Ice bucket in the room (which I bought at the lobby shop for home), the exquisite black marble wall of the lobby, the red uniform of the doorman, the Chinese uniform of the front desk, the yellow uniform of the porter.. unlike the modern suit and tie at the FS. I was there during Chinese New Year, and it was fantastically decorated... unlike the FS.
3) A lot of variety in eating choices - I think it has 11 different dinning establishments. The won ton soup is to die for... FS not so.. The Bake shop has some of the most delicious cakes in the city..
4) I love the Men's Barbershop - old fashion shave.. almost like an old men's club
5) The spa menu is much more extensive than FS... and they have special guests from time to time...
6) Laundry service is fantastic... I had an old T-Shirt that I used for the gym washed, and it came back with a note explaining that they stitched some of the holes in the shirt and they apologize for not getting a stain out (which I had for years), my dress shirt was missing a collar holder, and they put one in. The Shoe shine service is fantastic - Your shoes are delivered in a silk bag.
7) Breakfast buffet is extensive and exquisite... FS has a very limited breakfast buffet in the blue bar.
8) The car service to the Airport and to the hotel is top notched at the MO.. They now offer free wi-fi in the car.
9) They offer Acqua di Parma in the suites (the big bottles), while the FS offers Bulgari White in the little bottles..
10) The arrival gift that we always get is the Rose Petal Jam, which we love.