We finally procured the magical sleeper bus ride taking us halfway through Vietnam. We have had other overnight busses that have reclining chairs, but these you are supposed to lay back, stretch out, and get a night of Z's in.
I think all westerners are seated in the back because of our height. There is more legroom, but I can't say sleeping conditions were perfect. There is an effect greatly exaggerated when being on the back of a bus behind the axle. at low speeds a decent size bump will toss you up to couple inches. At high speeds you are flung nearly to the ceiling only a few feel above your head. It's like trying to sleep on on the end of a diving board during freestyle practice. I landed grunting out loud losing air and beating up my ribs from the rude awakening a few times. I was still more comfortable most of the time and liked the setup, that fraction of airborne time was fun, but the landing would keep you awake.
We watched an awful movie, "Salt", on the iPad because we had to drown out the sound of the pornographic horror film they were anoint on the bus. (That was weird)