I’ve stayed at the FS twice and, contrary to what Aventine said, I really enjoyed it (as far as skyscraper city hotels go). The rooms are modern, the views are great, and the service is acceptable for a hotel of its size. I’m a pool lover and the pool is stunning.
I much prefer the decor and general atmosphere of FS Guangzhou over the RC, notably the reverse of how I would rank the FS & RC HK properties.
To compare to a few other city hotels in China/HK (though YMMV):
FS Guangzhou is better than StR Shenzhen (only slightly), StR Chengdu, Shangri-La Xian, FS Beijing, both RC in Beijing.
FS Guangzhou is not as good as FS Shanghai, FS Hong Kong, RC Hong Kong, Rosewood Beijing, Peninsula Shanghai, RC Shanghai at Pudong.
No experience at MO Guangzhou