We should also consider that at the time laws such as the immorality act was passed black subjugation was a world wide phenomenon, when Verwoerd was in power, it was still illegal for a black and a white couple to be married in 37 of the states in America. Herman Giliomee actually wrote a very nice balanced article (I thought) in rapport last week.
http://www.rapport.co.za/Weekliks/Nuus/Apartheid-Was-dit-dan-net-boos-20120623
I doubt you will find an English version anywhere.
I find it ironic that Time Magazine voted Verwoerd in 1960 as one of the greatest leaders of the decade and in 1994 they voted Mandela into the exact same position.
If you want to judge apartheid then judge it by the morality of its own time as Gilliomee said.