I can't imagine seeing this in widespread use for quite some time. I mean 802.11n has already been out for a while and yet it few people have adopted it. Even if you do have an 802.11n router the vast majority of client devices only support 802.11g or earlier. You usually have a buy an additional adapter just to use 802.11n, so most people just opt for the cheaper 802.11g routers instead.
So given the large install base of 802.11g I really can't imaging seeing 802.11ac becoming widespread for 3-4 years.
So given the large install base of 802.11g I really can't imaging seeing 802.11ac becoming widespread for 3-4 years.