I have been using the ayrstone system for at least 12 years doing what you are thinking about and has worked great for me.  I think a line of site between the antennas is important(I use one at each location).  I am shooting around 1/4 mile. With that being said I think you can do the same with the ubiquiti equipment much cheaper.  At the time I thought the support from ayrstone would be worth it as I didn't feel technically savy enough to set them up myself.  They may be simpler now.