I enjoyed the first class sleeper ride back in 2005... the food was "interesting" but otherwise good, and I bunked with interesting characters both ways.

Someone told me that the SIN-KUL train is the only place in the world where you get stamped into a country (Malaysia's border control is at the SIN station) before you get stamped out of the first country (Singapore's border control is at Woodland, about an hour after you leave SIN). Something to do with the train line being owned by Malaysia ever since the Straits got their independence from Britain.