I have used numerous platforms, locally and abroad. The IG platform, app and internet, is by far the best, followed by TD Ameritrade. If I have to compare on-line bank trading platforms and throw PSG and Itrade in the mix, OST wins!
If you're looking at trading shares - SBK is fine. If you need to do technical analysis on shares get yourself something like Amibroker with a daiy data download (investordata.co.za) (SBK charts are poor to say the least). If you want to trade SSF and Index futures use Swordfish via dwt securites or IG Markets. Just a word of warning on IG - Be aware of why that charge almost no transaction fees. They make their fees from changing the spread slightly in their favour, but all and all this is a very good online app.