I see kulula.com is responding to SAA's low cost carrier Mango.

A price war has erupted between South Africa's two low-fare airlines, with private air carrier kulula.com announcing on Tuesday that it will undercut the fares of South African Airways' newly launched low-cost airline, Mango.
full story on M&G here
I don't see the kulula.com faithful changing airlines in a hurry - they know who has been keeping airfares down for the last five years or so.