Can folks share there experiences with flying Mango or other carriers in South Africa? What are your top 2 internal carriers?

To go where?

SAA - they fly a lot of routes with lots of daily flights
Fed Air - if you are going to private lodges inside SA

Air Botswana - only service, if you are going to Maun. No choice here so far!

I was thinking of flights from Jo-burg to Cape Town, Port Elizabeth to Durban, Durban to Jo-burg.

Is there no difference between carriers, so I should choose solely on price?

I flew Kalula from Cape Town to Joberg a couple of years ago. They weren't bad. One has to pay for any food/beverages. They're a bit quirky, too--the flight attendants dressed much more casually than normal, and their safety discussion was more light-hearted (although still factual). They seemed like they were trying to make flying more fun. It didn't bother me too much because they were much cheaper than SAA at the time.

I wish they still flew to Nelspruit.

We flew 1time https://www.1time.aero/aqueduct/1time/Booking from JNB to CPT. It was the cheapest, and fine.