Africa is as big as USA, China, India and Europe combined. You can't generalize. Companies are different since it's linked to it's location, background, political environment, history and so on. I would say the best deal for an expat is Ethiopian with 20 days on 10 days off, not sure about the pay but around 8-9k monthly then you may have a look at Rwandair for the rest as far as I know there is no commuting available. From your question I understood you're on the 737?