Personally, I think SA have a balanced team on paper. Their bowling attack of Ntini, Pollock, Nel and Hall is very good and they can afford to use Peterson in Nel's place if the wicket is likely to help a spinner. Kallis is good enough as the 5th bowler, with assitance from Kemp if required. Another option - which I feel will strengthen the team is to leave out Prince and bring Boucher at No:5, followed by Kemp, Pollock, Hall, Peterson, Nel & Ntini.
The batting is also good; Smith & DeVilleirs have shown signs of recent improvement with their opening and if they don't get out early, both can score quickly in the powerplays. Kallis can always hold things together if things get hairy at the start & Gibbs can be dangerous. Guys like Kemp, Boucher, Pollock & Hall might not be specialist batsmen, but have the ability to strike the ball hard & score quickly.
I think the various available options would certainly make SA favourites...at least on paper. Time will tell.

I am not certain what the reaction of the rest of the players to Pietersen's return really is, irrespective of what they say to the papers. They did rather well without him in th CB Series, playing like a true team after a long time. Now that 'KP' is back with all the media hype & expectations to follow, I won't be surprised if some of the hardworking 'regulars' are pipqued. Yes, he can bat aggressively to turn tables on a situation, but 'KP' does not make the whole England team; his body language seems to suggest that he has too much self-impotance and not sufficient respect for his colleagues.