AF's new 777 business class is great & 380 is pretty sub-par ... particularly for a long flight like JNB-CDG. Last I saw, they had a 380 on that route, and I'd certainly spend a few hundred bucks worth of miles to book away from that. If it's a reconfigured AF 777 (1-2-1), then I'd probably stick, though it would also depend on DL's aircraft to SEA -- if it's a 76, I might still switch book VS, though I wouldn't avoid a DL 76 as strongly as an AF 380.