Steve is making up the usual bulls*** again. My colleagues and I fly this route regularly in C class. (together we have done 20+ returns AMS - BKK -AMS on KL this year alone) No complaints whatsoever. Never been bumped. Good service, reasonable food. Good schedule ex-AMS with 8 PM departure, so after dinner and a movie I usually sleep for 6-8 hours.
Have a good flight.