It took us over an hour to clear JNB immigration in January, arriving in F. We had 2.5 hours connecting time and we ended up with 15 minutes in the SLOW Lounge before having to board our CPT flight. Very painful process ... they insist on seeing the eticket for your return flight, for example, and as is well reported will often deny entry if you do not have 2 blank passport pages facing each other in your passport.