The original Vumatel installs in e.g. Tamboerskloof is AON.
Pretty much all fiber they bought is GPON and all other provides are GPON (frogfoot, Openserve, octotel).
Only one that might go AON is cybersmart, but thats a tricky one since they only deliver to high density buildings like apartment complexes, it's why they can be so cheap.
I think a lot of CBD is AON and then maybe century city.
You don't need to care about AON vs GPON for a home or most businesses, since it can easily deliver Gbps speeds to most users due to the nature of how people access the internet, and in terms of upgrade paths, GPON already has newer cheap upgrade paths that move from 2.5/1Gbps to X-GPON which is 10/2.5Gbps to XS-GPON which is 10/10Gbps which e.g. AT&T are using in the US as cost has come down enough to be viable this year for standard install.
There's also faster ones already in research, the fiber itself is not the bottleneck, it's the equipment, and they can always decrease the number of switches to increase the speed to households.