Hi Swagare2,
CGNAT is used by ISPs to mitigate the use of IPv4 addresses. When you game on a CGNAT network you will basically be routed through the same external IPV4 address as other users but on a separate port.
If the game you are playing uses dedicated game servers, you will be fine; however if the game servers are not dedicated and its s P2P setup, then you will have problems and likely chance the incoming connection will be dropped by the ISP as that port will be closed (and you won't have access to open it). Also routing may be an issue, there will be extra hops in the network which increase latency.
CGNAT overall isn't great, as you are sharing a public IP address with multiple people. IP based advertisement targeting is one, if you visit Amazon or other shopping sites they may remember what you were browsing, and other sites may suggest similar content in advertisements. So if Craig down the road using Community Fibre has some weird kinks, you may also get them advertised to you!
Another potential problem is cyber attacks, If someone who also is gaming on a CGNAT network gets into an argument online, annoyed gamers may try and send a DDOS attack to that public IP address, which you are also connected to; so it could take out dozens of people who are using that same IP address as you.
CGNAT isn't great, but thats potentially why the price is cheaper. If i was you; negotiate with Virgin and see if they will offer you a better deal, as especially for gaming you want to stay away from CGNAT.
Hope this helps.
