I've stayed at the InterContinental, Grand Hyatt Erawan, and Sheraton Sukhumvit in the last 3 months.

Of those, I found no appreciable difference between the Hyatt and the IC: excellent (and comparable) facilities, service, rooms, and restaurants. However, both the Hyatt and IC are, in my experience, clearly superior to the Sheraton GS in each of those respects.