Hi David,
I have visited both over the Christmas/New Year, not with JY.
Australia would be my recommendation, certainly saw a lot. From cities to outback. Spent a month there and with 8 internal flights very busy, but saw so much of the country and going all that way wanted to make the most of it. I want to go back one day as still so much to see.
South Africa, visited friends they took me to all the 'tourist' places and one or two places that were not. Not somewhere I would choose to go back to, didn't leave a lasting impression on me at all.
Debbie