We took a cruise on the MSC Sinfonia from Cape Town to Durban, South Africa in December 2013. Overall, the experience was really, really good and actually compared very well to cruising internationally - we have been on the Costa Victoria along the Vietnamese coast previously and the Sinfonia experience on board and the ship itself was very similar.
The experience of South African ports however was shocking - Cape Town is a shed that took 2.5 hours in a queue to embark, most of that standing in the sun! Compare that to Singapore where we just walked through and that included immigration!
As with any trip, there is good and bad and its worth mentioning both:
Surprisingly spacious - there was space to move around the bed and we didn't fall over each other. However, shower is quite small and the shower curtain does attack and stick!