We burn 64 bits of the space (!!) on the "privacy extensions" changing part of ipv6 which is totally insane, and so you have a constant churn for 64 bits of the space. This churn complicates a fair bit of local area network address use.
You can get a static IPv4 block if you need it with business class service as well for that site. Despite claims it's a total pain to get IPv6 static blocks assigned by ISPS.
Your internal network can be subnetted however you like if you do any site to site VPN if using NAT. you are not dependent on uplinks at all.
Now if you have a business with a bunch of sites, not all may have full BGP etc setups. For example, you might do a dual WAN link - one fiber at 1gbps, another at 300mbps for backup. This is seamless with IPv4 in most cases.
With IPv6 - if your routes flap, you have to readdress everything on your entire network (!!!) for that site. And these updates are SLOWER and worse from what I've seen then WAN failover on the NAT. So then you can try to do the workarounds (network prefix stuff). So if you flap around a bit the network is done. This could just be a tech reconfiguring things and pulling a cable and putting it back in seconds later.
And the list goes on. Network prefix stuff is poorly supported. You are basically forced into dual stack mode. Etc.
IPv6 could blow routing tables sky high.
We burn 64 bits of the space (!!) on the "privacy extensions" changing part of ipv6 which is totally insane, and so you have a constant churn for 64 bits of the space. This churn complicates a fair bit of local area network address use.
You can get a static IPv4 block if you need it with business class service as well for that site. Despite claims it's a total pain to get IPv6 static blocks assigned by ISPS.
Your internal network can be subnetted however you like if you do any site to site VPN if using NAT. you are not dependent on uplinks at all.
Now if you have a business with a bunch of sites, not all may have full BGP etc setups. For example, you might do a dual WAN link - one fiber at 1gbps, another at 300mbps for backup. This is seamless with IPv4 in most cases.
With IPv6 - if your routes flap, you have to readdress everything on your entire network (!!!) for that site. And these updates are SLOWER and worse from what I've seen then WAN failover on the NAT. So then you can try to do the workarounds (network prefix stuff). So if you flap around a bit the network is done. This could just be a tech reconfiguring things and pulling a cable and putting it back in seconds later.
And the list goes on. Network prefix stuff is poorly supported. You are basically forced into dual stack mode. Etc.