Certainly no more complicated than any major airport. I didn't think security was overly trying but nonrev is insane unless you're using One Great Team passes.
You are held at the Delta desks until (IF) the station mgr gives the go ahead to dispense you to pp control and security. Desk super takes you and you have to beat feet to get to gate. You will meet nonrevs who have been there for days (some more than a wk) due to payload optimization (or his whim) S4s can look quite forlorn. Anyway, do your homework for hotels and guesthouses.
If you do use SunRock, they have driver w/sigh at arrivals hall. It's close to JNB--takes only a few minutes.