Had a look at you guys' website a while ago. I really like it, I share the same view.http://wellspent.co.za/resources/gap-cover/
You can break most of them down into a fairly decent pool of comparable features.
These are the options on the high-end from each insurer, but that is a function of having a percentage maximum rate of coverage, i.e. you can get cheaper options from these providers, but they max out at 200% or 300%.
Hope this helps! We can answer pretty much any technical Q you might have on GAP cover, so feel free to ask.