I'm no expert, so speaking under correction: with a shaped account, traffic is prioritised for certain traffic (e.g. web traffic) which means that other types of traffic (i.e. gaming traffic) are slowed down. I think this only applies to our international traffic, from an SA perspective.
So in SA, not only do we have crappy shaped accounts but in addition, they have puny caps!
I'll leave it to others to give more detailed info on shaped vs unshaped