I did the Capella, with the Verandah king room, nice, fantastic bar with peacock, fantastic CÔTE Michelin star restaurant but its a little bit clinical, also the swimming pool is below comparison with the Four Seasons, Spa is spectacular though.
I am still pushing for the FOUR SEASONS, in everything superior or equal with the CAPELLA.
The only thing i want to consider the Capella are the Verandah king rooms with outside Jacuzzi.
The Four Seasons standard rooms are nice but without an outside balcony...
They have all the same interior but otherwise TOP!
Secret tip, the NARA HOUSE in the Rosewood Bangkok. spectaculair!!!!
Last time I was in bkk with work. I stayed here and loved it. Bit far from the action though not massively expensive (if money is no object) around gbp300 a night
Siam Kempinski Hotel Bangkok
https://www.kempinski.com/en/siam-hotel