Expat work is pretty much the same all over, it will probably never be quite what you expect. You may make more money than you did at home....but it will come at a cost, one way or another.
Never believe what you are told at an interview, after all they are trying to talk you into joining them! And as for written assurances, I think you will find that at most expat organizations they can (and often do) change the contracts anytime they want, you can take it or leave it. Lets face it , we are only "scumbag engineers".
My best advice is go in with your eyes open, find out from the guys there what is really happening, and then make your decision. Be prepare to quit if necessary (easier said than done I know!).
PS. Does this mean I should pull my application for HAECO?...and I so like chinese food.