Here's a history of Airport Extreme announcements:
January 9, 2007 1st generation
August 7, 2007 2nd generation
March 3, 2009 3rd generation
October 20, 2009 4th generation
June 21, 2011 5th generation
June 10, 2013 6th generation
Current AE supports latest 802.11ac standard which can theoretically operates at 1,3 Gbit/s speed.
802.11 ad won't be here until late next year so won't Airport Extreme. I think Airport Extreme will be great Wi-fi router for couple more years.
Thanks for your information, that's really helpful.
I should buy the AE earlier, not just waiting.
Thanks for providing your enduser experience with the latest-gen AE, d.I had a 2nd generation Airport Extreme router, which supposedly supported 802.11n networking.
...
This weekend, I bought the latest Airport Extreme router, which supports 802.11ac. And it's made a DRAMATIC difference... I'm now seeing double the download speeds or more.
It's the best use of $200 I've spent in a long time.