Well, we don't see much S. African Chenin Blanc here either, so I can't say I've tried the best ones... I had Villiera and Morgenhof CBs and found them ok. I know you'll be a tougher taster for SBs, but I liked Steenberg, Neil Ellis and Mulderbosch SBs - very good QPR. They are good, but still not as good as NZ SB yet.
As for style, you get the mineral notes as well as the fruits, and they have some New World and some Old World nuances. I was just worried about rumors of some wineries illegally adding flavourings to wine, but I don't know what happened afterwards regarding this story. Did you have bad experiences with SA SB?