Also, just read this on digi.com. Any comments to this?
"Also note that antennas with higher gain focus the energy over a smaller area. Digi recommends avoiding the highest gain antennas in most applications because they are more difficult to work with.
Recommended antenna gains:
Omnidirectional: 3 dBi to 6 dBi
Directional: 8 dBi to 11 dBi
Note: High gain antennas are of limited use in extending the range in a non-Line-of-Sight (non-LOS) environment. In a non-LOS environment the obstructions contribute more losses to the system than the antennas are able to overcome. Also, the obstructions cause the signals to bounce and arrive at the antenna from different angles so it is desirable to have an antenna with a wide beam width and a lower gain.