Not to mention that IPv6 forbids fragmentation by routers, hence saving precious CPU (or ASIC) time.
I work at a relatively big ISP where we were an early deployer of IPv6 -- been running it for more than a decade. It was a bumpy road but we've stopped having problems for several years now. We even participate on Google's trusted partner programme.
I have IPv6 connectivity on all of my desktops (office & home) for over three years now and I don't remember to ever having a single connectivity problem with it.
I wholeheartedly believe that dual-stacking *is* the way to go.