One of the ISP participants in WorldIPv6Launch day is AT&T. They are working towards a goal of having at least 1% of their wired residential customers have IPv6 connectivity. A recent post on the NANOG mailing list states that they have started this with 6rd.
6rd was first launched into production by a residential ISP in France, Free.fr. Comcast was also looking at 6rd for their deployment as part of their trials. Their 6rd trial ended June 2011, and they have since decided that they will deploy native dual-stack to their customers.
Similar to 6to4, 6rd can work for getting your users connectivity, but does require the CPE or directly connected computers to understand and be compatible with 6rd. Another issue would be overloaded relays or what happens when one goes down. Users of 6to4 see this frequently, however with 6to4 it can be a bit more the troubleshoot which relay is having the issue. With 6rd it should be more obvious, and thus quicker to address since the relay is only operated on the residential ISP’s network.