I am going on holiday to USA and intend using my British passport. I also have a South African passport and have dual citizenship. Would I be able to get a visa waiver or would I have to get a normal visitors visa?
As a UK citizen, you the VWP method is available to you. Use your UK passport to check in to your flight and present it to the US CBP upon arrival. The fact that you also have South African citizenship will not be relevant. (If for some reason they ask if you have any other citizenships, tell them - but it won't affect anything.)