Dubai's electronics are not significantly cheaper. Your best best is to try during their Summer (on now) and Winter shopping festivals and to hunt around the larger malls (like City Center, or in Computer Street). You may stumble across a bargain, but I've found that it's not cheap enough to risk the hassles for a warranty claim.
Having done the shopping thing recently ... when I look back - I'd say rather buy in SA. Use your money there to enjoy the experiences that you cannot buy back here in SA.
Unless you are looking for something horribly expensive here - rather buy in SA.