I got this (and the Amped Wireless High Power Wireless-300N Smart Repeater (SR300)) to extend my wireless network to my workshop, at the back of the yard, about 250 feet from the house. This is far enough away that I don't get even the smallest amount of the WiFi signal from the house. I wanted to watch TV while I work, and I also needed to be able to use a phone there.
I could run Cat-5e wiring underground, but that would require digging a trench across the yard, and also running the Ethernet cable from the router inside the house to a demarcation point at the exterior of the house, which would be quite a bit of work. Using this antenna--two of them, actually, one at the house and one in the workshop--I'm able to get a very strong and fast network link in the workshop.
It's incredibly easy to set up. The antenna is designed to be mounted outdoors, and they recommend using 25 feet of Amped Wireless Premium Outdoor 25ft Antenna Extension Cable (APC25EX) to connect the antenna to the Smart Repeater. Instead, I connected the Smart Repeater directly to the antenna with the short cable that comes with the antenna, and both are sitting in a closet at the edge of the house.
I would probably get an even better signal if I mounted the antennas outside, but it works just fine for me with the antennas inside. In the workshop, I aimed the second antenna in the general direction of the one in the house, and it works great. There are a few trees between the buildings, and the signal still gets through.
Without doing anything to really optimize things, I'm getting 2.5 Mbps downlink, and about half that uplink. This is slower than my router's upstream connection, but it works just fine. I'm really enjoying having the network and phone in the workshop.