Well I came back from SA. Spending there a few last months. Anyway from the start. I was using Vodacom for local calls and data. HSDPA work even in some areas not covered on their map(for example St. Lucia). You can see on your handset display whatever your BTS is either EDGE Enabled or EDGE, 3G and HSDPA Enabled. Vodacom Data in bundle are fairly cheap. Sound quality is not as good as in Europe. Now about the roaming. I have been using UM+, plus some Czech and Cypriot SIMs as back up. What have strange, let say after some days roaming in country I have lost coverage for hour or so. It have happened several times on different SIMs. You will get much better sound quality, when using JustVoip on UM + than on Vodacom. I would say even better than on local calls. Couldn't receive any calls on UM+ when roaming on CellC, so Vodacom or MTN is way to go. You can get discounted airtime for local SIMs. Normally about 5 to 10 percents. More choices in big cities. Elsewhere the best is to pop up in to the PEP Store.