I had IPv6 from TWC, then for a month or so before the merger it went MIA, and then about a month after the merger it was back. For some reason I get a more reliable path to my IPv6 gateway than IPv4, so I missed it quite a bit.
Spectrum/TWC has had IPv6 via DHCPv6 with prefix delegation for a few years in Louisville, but only with a select set of modems. A Juniper DOCSIS 3 wouldn't work for me while a Motorola had no trouble.
The problem is usually the $50 wireless access point most people bought 5 years ago doesn't pass ipv6 through.