I don't have anything new to add to this thread, but just had to echo the now-nearly-200-pages of previous posts touting what a fantastic property this is. The hotel itself has good bones; while I understand the quibbles with some of the dated interior elements, the various spaces all hold up well (although I must admit I found it awkward to have to tramp through La Sala to get to the pool deck) and largely to my taste. The service is everything one would expect from a luxury hotel in Southeast Asia.
What really sets this property apart, however, is SPG. I could not believe how generous the Platinum benefits are. My wife and I enjoyed a suite upgrade (to an xx12 Luxury suite) w/o an SNA, drinks every evening, hot lattes in the room every morning, amazing breakfast spreads at three different venues, fresh laundry each day, and an occasional afternoon tea. All for my corporate room rate which is less than I usually pay for some nondescript Sheraton in middle America.
I was impressed--but not surprised--to meet Mr. Chapman himself our final evening as he strolled the Library chatting up guests. He clearly takes pride in his property, as he should. Unlike many in this thread, I am not a Bangkok regular, but when I return I'll certainly be back at the SGS. Can't believe I was *this* close to staying at the StR instead...
ETA: Almost forgot to mention one unexpected bonus: the gym is fantastic! Was really surprised to find a full (staffed) weight room in addition to the usual hotel cardio fare.