Howzit!
I don't live there, but I have actually been to Mpumalanga! I spent a month working in Nelspruit. In a lot of ways, it reminded me a lot of northern California, which was a surprise for me.
When thinking of early retirement life, I often consider the other places I've traveled to, and how it would be to live there for a longer period of time. Mpumalanga seems like a good place for it, especially with the nice climate for growing things.