Other than that, about the worst thing they said about my connection was low bandwidth and high latency. Of course, that is actually an AT&T feature set
My HE IPv6 gateway is in Miami so it performs reasonably well considering. But no complaints, a static routed /64 and another /48 if I want it for free!
And yes, if you run dual stack without an IP on the six side, performance of your four side will absolutely suck.