***Update June 12, 2014- AWUS036AC is now in stock and available for purchase here.
Available in May June, Alfa's AWUS036AC is a new long range dual antenna 867 Mbps Wi-Fi USB adapter compatible with Windows XP through Windows 8. It features two RP-SMA antenna ports, and two 5 dBi dual-band antennas.
AWUS036AC is capable of receiving and transmitting on both the 2.4 GHz and 5 Ghz bands. With 802.11ac standard routers, AWUS036AC can acheive throughput speeds up to 867 Mbps, almost three times that of the 802.11n maximum of 300 Mbps.
The dual antennas and high receive sensitivity also allow it to pick up Wi-Fi signals from up to 2 times newer internal 802.11ac Wi-Fi cards.
AWUS036AC is backward compatible with 802.11n and 802.11g Wi-Fi equipment. The faster connection speeds allowed by 802.11ac require connection to an 802.11ac standard router. 802.11ac technology cannot increase ISP speed on a specific computer. However it can improve network-wide performance if all computers and the router on the network are 802.11ac compatible. This is because one of the improvements of 802.11ac Wi-Fi is the ability to handle more users on the same network with better bandwidth management. Though ISP speed cannot be improved, throughput to the ISP can be in this case.
Alfa's AWUS036AC will be available for sale here at Rokland.com in May. Rokland is a leading authorized distributor of Alfa Network equipment. We have been doing sales, service, and installation of Alfa equipment since 2007.
Military and First Responder 
Works out of the box. Updating drivers manually via Device Manager to ones given by Alfa Networks works good and improves performance in range of finding networks, in my case. But the provided software does not work with both of my Windows 8.1 machines, desktop and laptop.
Link to my Dropbox error log folder and install file used:
https://dl.dropboxusercontent.com/u/44423566/USB%20error.rar