My thoughts are pretty similar to comments above. PH has better breakfast than Rosewood/Kempinski. Design wise both Siam/Sindohorn Kempinski are the least attractive.

Outside of those choices, I think FS Chao Praya is the best overall BKK hotel now. The Siam is quite special as well. I don’t get the appeal of MO BKK, I find it too stuffy. I am not crazy about Capella either.