For me??? I had to learn the hard, and fairly expensive, way that high gain GND-Plane antennas that kicked-ass in fairly flat terrain just did not work at all in hilly terrain and deep in a valley. Co-linear antennas for VHF / UHF are pretty much useless where I live today. Even a 5/8-Wave GND-Plane is too high gain for here. 1/4-Wave, maybe even 1/2-Wave, and that less than Unity Gain Discone, seem to work best here. Live, learn, develop buyer's remorse.