Well the Sandton neighborhood of JoBerg has the best Holiday Inn in the world. Not what you were after? It is very good and has some amazing suites for an HI.

The airport IC is possibly the best hotel on airport property in the world. Most expensive too. Again, not what you were after?

I always stay at the IC in Sandton which is pretty nice and has some excellent high end suites. But it's not at the luxury level that most of us are accustomed to.