Business account is completlely unshaped. No punsihment for high usage and full priority on downloads and torrents.
Note: If you do get a business account and plan to use torrents, you will have to turn protocol prioritisation off via Clientzone (logging in on Afrihost's website)
Optimistically the maximum download throughput on a 1Mbps line is gonna be about 125KBps. The quality of your line, distance from the exchange, etc are going to be a factor.
Concerning other ISP's, the only other ISP that I have heard mostly good things about is OpenWeb. Their Unshaped Package is their Platinum Uncapped. See here:
http://www.openweb.co.za/platinum_uncapped.html
This isn't a bundle, does not include the ADSL line and costs R789pm. (The DSL line would be about R150 extra)
Afrihost should be the best value for money. Another thing is they definitely have the best support system out of all the ISPs. Except for the regular email support, you can get support via MyBroadband Forum, Facebook, Twitter, Google+, and Live Chat Support via Afrihost.com