re: my new ASUS RT-AC56U came in today..damn fast shipping from the Egg

Phones are low-hanging fruit since we're still talking about single spatial stream devices, and they still won't benefit from AC without having another AC-capable client or a gigabit ethernet client on the network, and still it's only beneficial if you're actually reading or writing large files from your local network using your phone. It will probably be another year before we have a decent selection of higher end wireless AC routers that actually offer significant better antenna power, and every single wifi-enabled device is using an 802.11AC adapter. And even then, if you aren't in an upgrade cycle for shiny new electronics, the number of available AC devices on the market is irrelevant.