Due to the runaway prices in KNP I’m going to have to consider camping there in the future and the only reason I haven’t until now is the mission involved to get all the kit there from KZN (family of 5)
I have cruised through all the camping sections south of Shingwedzi many times to check things out and my personal favourites are Balule and Maroela, due to the semi bush camp feel and there is good game viewing in the area.
Tsendze looked cool, but I hate the Mopani area for game viewing.
Below is a list of camps that offer camping, please have your say with reasons (Maybe mods could create a poll

Berg-en-Dal
Malelane
Crocodile Bridge
Letaba
Lower Sabie
Tsendze
Balule
Maroela
Pretoriuskop
Punda Maria
Satara
Shingwedzi
Skukuza