mobie - sounds like quite a good offer to me! Especially if the housing and wheels is sorted out and you receive a food allowance of $50 per day. But the decision depends on where you are in life, i.e. wife and kids also going to join you up there or will you go up on your own. It will be quite a bit harder there if you have family.
Lagos has its fair share of issues, but it really depends what you are accustomed to. There are lots of expatriates there that have a fantastic time and really just make the best of it.
As for being the worst country in the world and living with savages...we all have our opinions!