I have been on a dual stack IPv4 and IPv6 connection for a while now. IPv6 is the preferred protocol. I think I'd have noticed if there were widespread IPv6 issues. It used to be worse, but that was years ago.
It is not widespread. Not for the major services at least. But saying IPv6 is better than IPv4 with lower latency due to better routing and lower overhead simply is not true. Apparently there are other factors at play that also matter a great deal and still lead to teething problems.
