If I have no children accompany with, I may choose Grand Hyatt. But now I have two young children, I would like to choose four seasons because in GH's lobby, there's restaurant and when children go down everyday, it would be crowded and too many people in GH's lobby.
I didn't try FS's spa because it's rather expensive. It cost around 1300 baht per hour even for basic thai massage. The spa is even more expensive. So that I chose to have spa at outside.
I just came back from Bangkok and had stayed at a new hotel called the Millenium Hilton Hotel which is next to Peninsula and also stayed at the Grand Hyatt Erawan for the last night I was in Bangkok. Well, same as Peninsula, the Hilton is on the other side of the river, so either taking taxi out or take the free shuttle boat to across the river to catch the BTs. In my experience, is relatively convenienve gei, but hence those free shuttle boat only operates until a certain hours, so if is after hour when there is no shuttle boat to catch, the only option to go home from the Siam or Emproium will be taxi. And as you all know what is the traffic like in BKK. As for the Grand Hyatt, I guess I had put too much expectation before I went in, in fact I think is a bit old lor. Oh, forgot to say that the pool at the Hilton is excellent as is located on the 4th floor of the building, very cool and windy, good for tanning!