Southern Africa would be my call. Best bets are South Africa and Namibia. Stay well away from Somalia, Nigeria and DRC.
South Africa is one of the few countries with any decent standard of living. I have worked all over Africa from Tunis to Cape Town and it is pretty rare for anywhere to have anything close to a decent level of service, accommodation or professionalism outside or South Africa or Morocco, Tunisia and Eygpt.
The South African and Namibia CAAs are more helpful than most of the other ones I have encountered. Most of Africa especially West Africa you get the feeling that they are doing you a favour by letting you fly their in country.
To be honest it's unfair to say not to go to the rest of Africa but it depends on what you are trying to achieve. If it is a change of lifestyle, see some new scenery, have some fun but remain reasonably safe and professional then go with the above.
However if you have an appetite for shockingly bad hotels, poor service, poor ATC, scams and dodgy deals then head for West Africa.
