While not surprising given the lack of uptake of IPv6, I have been enjoying it through the Airport Extreme, which can assign IPv6 addresses automatically to connected computers. This greatly simplifies my ability to access my computer when I am away from home, especially since I can access multiple computers behind the router without having to mess with NAT and port forwarding.
Unfortunately, the iPhone won't go to an IPv6 address in Safari, as far as I can tell.