Ok just got back. Hit nearly a mile max in a residential setting...
1) this thing is pretty directional. I found best results are almost perpendicular to the ground @ 500ft agl
2) get an app like Vision Plus
https://play.google.com/store/apps/details?id=com.aryuthere.visionplus so the telemetry (including WiFi strength) updates quickly and often. Constant feedback was crucial in determining proper antenna angle
3) Take your first flight in the dark. This antenna has some distance on it, I can't imagine LOS during the day and the LEDs in the dark helped tremendously.
4) Installation wise, it was simple but like DBS says the hex screws on the extender are crap. I stripped 2 of them being careful. If you strip them, use a flat head slightly larger than the hex and a hammer to create a flat groove over the top, then unscrew it like it's a flat head screw. Cheap metal, so it shouldn't take more than 1 hit with the hammer. PM me if u don't get it.
All in all, pretty impressed. Will try fpv quality settings tomorrow if I have time.
http://www.flytrex.com/mission/quadcopter-p2v-v3-0-stock--bill-brunner-jUz7iAB2/