Why would ipv6 be more reliable than ipv4? I’d say it’s the opposite: many times I’ve found websites with AAAA registers that pointed to a dead server. I mean, if you’re going to blame cgn for your problems, let’s steep to your level.
Analytics? Forensics? So you’re telling me ipv6 destroys my privacy. How is that a pro argument?
IPv6 has smaller routing tables, doesn't required routers to recalculate header checksums and doesn't support packet fragmentation (the endpoints are required to handle that). This allows more efficient router designs despite the larger headers.
The specs on the router claimed that the highest speeds could be reached with ipv6 support because you could then avoid the overhead of nat for your ipv4 addresses. So that may be what they are referring to. Nat does create overhead.
Also, MTU path-discovery is a pretty big deal in terms of performance, as IPV6 does not allow packet fragmentation. Which should improve performance aswell.
This is something I don't really see anybody mention, but IPv6 doesn't allow packet fragmentation as far as I know -- which means you don't get the sudden performance degredation (and extra data loss probability, etc.) that comes with using the wrong packet size. I expect that boosts performance but I haven't had a chance to measure.