I always have enjoyed the Living Room HH at the SGS. The ambiance is much better than most hotel lounges. The seating is comfortable, the alcohol is decent, the service is pleasant, and the music is an added bonus. I get that not everyone may like the music, or may expect more food like a lounge buffet. I have always felt relaxed there during Happy Hour. Too many other hotel lounges are overcrowded during happy hour times. The Living Room HH has been one of the reasons I appreciate the SGS.
The Living Room never promised to be a buffet lounge. It is nice that the SGS offers Happy Hour free flow drinks as a benefit to Plats(or higher) or to those who book a room that comes with HH. I don't enjoy HH at BarSu as much, however choices are good. I haven't tried too many Marriott/SPG lounges in BKK, however I thought the Happy Hour alcohol selection was better at the SGS than at the Athenee lounge.