I agree with planr. It really depends on the person. I can't sleep at all in a coach seat unless I'm totally wiped out. And even on the angled lie-flats I don't sleep that well. Part of the problem for me on any airline or airliner is that the deck flexes everytime somebody walks in the aisle. I'm always feeling that as I try to sleep. But in spite of all that, I still much prefer THAI Business class compared to economy, and don't think I would come out ahead by using another carrier and stopping somewhere on the way to Bangkok.

My gf can sleep far more places than I can . . . bus, economy coach seat, etc. Honestly, Business Class would be a waste for her as she's small and would sleep in a coach seat anyway.

Then again, some people can sleep anywhere:

I shot this through the windshield a few years ago; this truck was cruising down a highway in Isaan at about 100 kph!