These are all fairly small operators and there's a good chance that the reason why these tours are all of a similar price and intinerary is because they are all actually provided by the same South African company. For example, a tour of Cuba booked with Travelsphere will be subcontracted to Havanatour with the guide and driver being employed by Havanatour and not Travelsphere. It might be worth asking each of them whether the local staff and rep etc are direct employees or a local sub-contractor. If the answer is that they are local sub-contracted staff then ask them for the anme of the local sub-contractor. if they all sue the same one, then it's not going to make that much difference as to which one you book with as to regards the service once you actually arrive in South Africa. The only real difference will be how each of them deals from head office with complaints etc if things go wrong.

SM