I recently purchased this to increase the wireless signal within a 2-story building that has numerous walls in between the modem on the second floor and the computers on the first floor. With this antenna, I'm able to boost the wireless signal from about 50% to about 65% as long as the antenna is pointed at exactly the right location. A few degrees up/down/left/right will tend to decrease the amount of signal by a few percent.
When I further compared this device to the Super Cantenna (rated at 12dbi) WIRELESS GARDEN SCB03 Cantenna Wireless Network Booster, this antenna clearly performs better. However, when this antenna is compared to the Hawking HAI17MD Hawking HiGain Directional Antenna, mini indoor, 7dBi - HAI7MD, the difference is minimal. Pairing this antenna with a Hawking HSB2 Hawking HiGain Signal Booster version 2 - HSB2, I was able to receive 100% signal which surprisingly even outperformed our commercial grade D-Link 7700AP access point (the D-Link typically provided about 70-75% signal without any enhancements or boosters).
All in all, a cheap antenna that does work (although perhaps not as well as one would expect from something with 14db gain) but requires exact placement and a booster to really make it shine.
Note: You may need additional cables/connectors to hook this antenna up to your network. You will probably need at least an N-Type male to Reverse SMA Female connector (which you can get from the Trendnet Outdoor Arrestor Kit) TRENDnet Outdoor Arrestor Kit (Includes Reverse SMA to N-Type Converter) and if necessary, an antenna extension cable TRENDnet N-Type to N-Type Cable / 6M (19.7t.) or LMR400 N-type cable equivalent (try eBay).