The Apple claim is so hand wavy as to be meaningless. Without any hard data and like-to-like comparisons, the most that can be said is that IPv4 and IPv6 have

The Apple claim is so hand wavy as to be meaningless. Without any hard data and like-to-like comparisons, the most that can be said is that IPv4 and IPv6 have different routing policies and this may attribute the differences in latency. As such what and where you test will affect your results. That being said, Apple’s IPv6 policy is probably the best thing being done to encourage adoption. However, they are not adopting the policy due to performance reasons, but due to necessity given who their ultimate customers are (cell phone companies). IPv6-only as a term has been heavily abused. A truly IPv6-only network has no access to IPv4 resources. If it does, it isn’t really IPv6-only and relies upon IPv4 addresses and NAT to work.