They're decent. Just make sure you scrutinize your first few bills with them, as with mine they added a whole lot of subscriptions that i never asked for and only found out i was paying R50+ each month a few months later. They claim that they added the 'standard' tracker service which is free for teh first 2 months, and thereafter it is charged for. I'm not sure tho if this is the service provider or Vodacom itself...
Cheap scam i tell you.