I think one carefully needs to understand exactly what you are after here Marcus. There are plenty of places to see wildlife and the regular parks like Kruger are as good a place as any to do that. You will see plenty of wildlife in those parks and, if you are just interested in seeing the animals, then you can’t really do much better than a self-drive in those parks. You will get plenty of opportunities to aim your camera at wildlife here, but if you are happy to walk away with point-and-shoot type images for the most part, then look no further. The main “problem”, photographically speaking, with these parks is that you are restricted to your car and a limited network of roads. In the private reserves, they roads are less of an issue and the game vehicles will more often than not drive off the roads to give you a better view of the subject. If you get a good guide in the private reserves who is catering for your specific needs, they will know how to place the vehicle to provide you with the best possible photographic opportunity. They understand the need to have the light in the right place (you can tell them if you want your subject lit from the front or you want side light or back lighting depending on the mood you are trying to create), the need for a clean, uncluttered background as well as an uncluttered foreground without those pesky blades of grass or twigs in front of the subject, etc. Unfortunately, as has already been mentioned, there is a premium to be paid to get these opportunities.
So, really, you just need to decide what exactly your main aim is. Is it just seeing the wildlife and getting reasonable shots of them or do you want to walk away with the potential of some seriously great wildlife shots (from a technical photographic point of view).
Anyway, you are bound to get lots more advice here still. I already mentioned Motswari as a great place to try for Leopard shots – if you do go there, you could not do much better than asking for Chad Cocking as your guide. Chad is a top notch wildlife photographer in his own right and there are few people that understand how to get the best possible shots of those animals in that area than he does. Here is a link to some of Chad’s work - http://www.outdoorphoto.co.za/galler...e=chad-cocking
. If this is the kind of wildlife photography that you are wanting to achieve, then, in my opinion, a private reserve is the way to go without a doubt.