I'm a poor uninformed traveler in Los Angeles, about as far from any insight into South Africa as anyone can be, so take my comments for what they're worth.
I've visited the area many times over several decades primarily because the game parks (Kruger, Etosha) were so spectacular. I tend to maintain a traveler's interest in the area because of that.
It's probably "safe enough" to go and enjoy yourself but a cautious person will do a bit of extra homework before going there, and keep a careful eye out. You're worth a lot of money, and the bad guys know that local law enforcement won't be on the scene as promptly or with as much sympathy for the western tourist as say the LAPD. The reason it's safe in spite of that is that the bad guys are still a tiny minority so it's hard to get unlucky.
The last time we visited we drove to Kruger, as has been our custom. The trip was uneventful. We took a longish break in Nelspruit and wandered around. The town seemed much more a beehive of activity than before. I think we were the only white folks in sight, but it wasn't at all uncomfortable or worrisome. It was just a bunch of good folks going about their business.
On the other hand, the readers' column in the M&G I mentioned above really shocked me. There are clearly a few folks willing to express strong hatred for white people. You just have to make sure to don't cross paths with them. My comment that I'd probably cross SA off my travel list wasn't entirely a safety issue - visiting Kruger by air from JNB provides pretty much a 100% safe cocoon - but a culture-shock reaction to the letters.
A tiny problem is the poor access to details of what kind of problems exist, which would help avoid trouble areas. The M&G has apparently changed editorial policy in the past couple of years and no longer seems to publish reports of casual crime. There's a usenet newsgroup, something like soc.southafrica, that probably still has a lot of information. For a while it was the height of foolishness to visit downtown Johannesburg even at noon, while Capetown was thought to be well controlled. It would be nice to know how that's changed, if it has, and if it matters to your plans.