Everything, from the polite welcome, to the relaxing reception area, to the huge room, to the lovely polite staff, to the pool, was fantastic.
Stroll down the approach road, and within 50m you're in a peaceful oasis of stylish modernity (which you need in a full-on city like Bangkok). We booked a Metropolitan room, which at 54 sq m was so comfortable and spacious - the bathroom was huge and so well laid out, the bed and linens were luxurious and comfortable, and (and I'm not one to normally rave about these things) but the toiletries were the most amazing, incredible-smelling I've ever experienced (this smell permeated the whole hotel and was amazing). The pool outside was huge, and so relaxing, with great poolside service, the gym was lovely - all in all a fantastic experience and we wouldn't hesitate to go back. We stayed at Siam & Siam after being here and my word it was a come down!
Didn't eat at the restaurant/have breakfast, but there is a patisserie in the French embassy 50m away which was excellent.