This is the second time I was staying at a Mandarin Oriental hotel (first was in China). I had the best experience this time too - I stayed there for 2 nights this week with my gf , and my parents who were celebrating their wedding anniversary (which was acknowledged several times throughout our stay).
Everything was great, from the initial welcome, the concierge services, to the pool and to when we left.
Not cheap, obviously. But totally worth it in my mind (dont expect a party there though, focus on Pierre Gagnaire's food instead!)