South Africa - excellent
Mozambique - good comms, controllers can panic a bit when there's more than 1 aircraft in the pattern (as with lots of places in Africa - the radio just goes quiet - the cue for you to start chatting th the other aircraft to arrange your own separation)
Swaziland - good
Botswana - good
Zim - ok to clueless in the day, can often all be sleeping at night
Namibia - good comms, good controllers
Angola - hmmn, some areas good comms, others not, controlling leaves somethign to be desired
Congo - dreadful, can do a whole flight without saying a word
Nigeria - very busy frequencies, comms OK, controlling ok, especially considering the situation they often find themselves in
Ivoire - Half french half english, not the brightest boys either. comms are ok till you go west then its HF
Liberia - was fair last time I was there, they had just got new radios.
Sierra Leone - you're left to your own devices a lot, but not dangerous
Tanzania - comms OK, except coming from Malawi side, theres a bit of a hole there, the controlers need to be watched, I've had incidents there
Guinea - poor comms & controlling
Kenya - good comms, fairly good controllers, can go to pieces when its busy though
Generally you need to keep your wits about you, and keep a lookout, esp. outside & TCAS. Best to have a chilled attitude to the chaos too, getting angry gets you nowhere.