Start by looking at routers for IPv6 support. And what do you see? Total crap across the board. Here's some of the issues I've seen. Routers that have no IPv6 support (common for ISP provided routers.) Routers that have NO FIREWALL for IPv6. Routers that crash every 3 minutes after assigning an address. Routers that don't support the exact combination of network details to setup IPv6 on your network (there are multiple ways to deploy IPv6.)
What about if you want to use features like UPnP with IPv6 (something that would probably be useful for some software given that IPv6 is supposed to give you public addresses but firewall it on the router.) What I've found is there's really just one UPnP library that every router uses even though it sucks. miniupnpd. This is a library that can barely manage to handle different types of addresses. It's really a mixed bag whether an IPv6 firmware will have miniupnpd enabled and if its built for IPv6 (and if anyone bothered to test it.) The odds go down dramatically.
If you manage to get a router with IPv6 at home working alongside other useful Internet standards made for it (since 2010) color me impressed. You probably buy a lottery ticket at that point. Because if testing IPv6 deployments for the past 2 years has taught me anything: its that no one really cares about this shit. Present day, present time. You still hear people telling others to turn IPv6 off for some vague reason ('security', 'bad', 'problems.') These people don't really have a clue. It's all just a massive cope because they tried to get it to work and failed. And after the shit I've said I can't say I blame them. But I also want to note that their conclusions are BS.