Where have you been?
MTN are much cheaper in the smaller bundles and all of their bundles have OOB=IB for the duration of the bundle (60 days from purchase, not up to 60 days).
At this stage the benchmark for me is 1GB+ per month. There MTN and Vodacom are still exactly the same. If you are on Pre-Paid or manage your bundle correctly then OOB is irrelevant.