Never mind 4Mb, my 384kb connection has been awful as well.
Feels like 56k when browsing.
I am sitting on the fence and am not going to "upgrade" until such time as the service provided by Telkom is free of obvious network issues.
I do not download much, so for me to pay extra money for a "faster" connection is not necessary, considering that it may not be all it's supposed to be.
Telkom may be "upgrading" people, but probably just to capture more market share for itself.
That is their way. Money first, service last.