i would agree with the exception of this on-the-go sim. it's been solid since I got it. their support is utterly useless but as long as you refer to this thread to get the APN it's pretty much set it and forget it. Monthly billing via credit card.The fact that you are considering Supersonic so scare you, should scare you alot. Read the reviews, worst possible ISP in SA. Alot of other options out there.
no e-sim I am aware of but even if they did, i'd stick to old school.