sand or rice
I've worked at both and I would not do it, first off I was at NAS and they will find a way to screw you so unless the contract is for a hard and fast 16k a month don't believe it. Second I would be concerned about NAS's future going forward, it has never come close to braking even much less a profit and how long a future the place has is truly a mystery. If you are in China and coming close to finishing your current contract Tianjin is offering about the same money.
In the end every guy is different, if your an absolute whore for the money and nothing else matters then I guess that is your choice, I personally would not trust the Saudi's, and this is based on MY PERSONAL EXPERIENCE, they may offer the moon but my guess is they will find some way to weasel it down. I have watched them do it to too many guys.