SIN...

Grand Deluxe is the newly renovated mini-suites, in the Grand Wing. No access to lounge, unless upgraded by Diamond status (don't count on it though).

Club is the same room type as Grand Deluxe, mini-suites WITH access to lounge for breakfast, afternoon tea, and evening cocktails.

Executive Suite is a much larger suite, with a full living room and powder room, and bedroom with dressing area/closet. Very nice.

BKK...

Grand Deluxe is a standard room, no lounge access or anything.

Club room is basically the same but with access to lounge for breakfast, afternoon tea, and evening cocktails.

Note that BKK has a Suite Rate of $255/night, which is a great deal including all services, and airport transfer.