As far as i know, both South Africa and Rhodesia had apartheid systems with minority white rule. Was there any general difference between the two countries and their apartheid system and how they treated black people?
I can also try and put it in another way: let's say i was a black person, would i rather want to live in Rhodesia or South Africa during their apartheid era?
Conceptually, the two countries had quite different political systems with regard to how minority white rule was maintained.
In South Africa, apartheid theory stated that blacks were not part of the nation. Rather blacks belonged to their 'homelands', formalised in 1970 when blacks had their citizenship assigned to one of 10 homelands. Blacks could of course not vote in South African elections. Only about half of black south africans actually lived in these homelands, with the rest living in South Africa proper either as contract labour or illegally.
In Rhodesia, white political dominance was maintained by restriction of representatives of black voters to a small segment of the assembly. However there was not the same 'homeland' concept as in South Africa.
This is an overview of the question as it applies conceptually to questions of 'what is the nation'. Maybe someone else can give more information about realities on the ground.
I answered a question similar to this relatively recently - if you have any follow up questions, or anything more specific you would like me elaborate upon, please feel free to ask!