During a recent move, I did some research. We need a local server for it's speed, so the international option just doesn't cut it for us.
First, the cost of local bandwidth (for managed dedicated servers) ranges from 2.5 cents (Hetzner) to 14 cents (other ISPs) per meg. For Hetzner, this equates to R25 a gig or R750 for 30 gigs (NOT R3000 as quoted by VioAdmin in this thread).
Second, we used to host with ThePlanet in the U.S. but we got a better, faster server for about R1000 per month less at Hetzner because we weren't using the ridiculous amounts of bandwidth given by overseas ISPs. At the moment we only use about 15 gigs per month.
Third, we are not subject to fluctuating exchange rates and we can claim the VAT back from SARS - which only helps to reduce the cost further.
With that being said, I must confess that when we were hosting with ThePlanet, there was not one security issue of this magnitude in 3 years (that I am aware of).