We are at least at the ISP I work for. That is a major project for us this year, but any network engineer can tell you that deploying IPv6 is not straight forward at the ISP level. Getting everyone together on how to have some standard form of addressing from different entities is the toughest lift. Get Juniper, Cisco, and Arista on the phone and you will get three different ways on how to deploy it. You don't want to be the odd duck once the dust settles.
Interesting. What are the big differences if you're allowed to talk about it? I have no doubt that the IPv6 rollout is difficult, I helped move some simply cloud stuff to IPv6 and even that had a few issues. I'm much happier without the heavy layers of NAT though.