My client has been hosting using an IIS-based server in South Africa, because it gives a clear speed advantage to the customer base which is largely South Africa-based. However, while travelling in Japan and Australia, I've noticed the huge deterioration in speed when accessing the site.
Up till now I've avoided pushing the site onto a European cloud host because of the definite deterioration (we've usually used West Europe with other clients), since the sea cables run to Europe I believe.
Recently Microsoft launched what appear to be data centres in South Africa, but I'm not sure what the full capabilities are.
If our customer base was split 80-20 between South Africa and the rest of the world outside of Africa, what would be the optimal location to host and would the Azure expansion to Africa influence that choice, and in what way?