We're using a combination of Ubiquiti's 900MHz and 2.4GHz radios to connect approximately 15 well sites with EB2's via a VPN to our central office. Use 2.4GHz if you have a clear line of site over a longer distance (one is 15 miles). However, if you have trees (and we have lots) 900 can generally burn through most for a distance of a couple of miles. (the water in the leaves scatters the radio waves). We get a number of re-try's 20 or so a day per EB2, very few actual read failures. We have both multi-point access point using omni-direction antennas, and Yagi's for point point connections.
Another note, 900MHz is used be a lot of other devices, so if you are in an urban area it might not be the best choice. Ubiuiti has a number of on-line tool to testing a connections before installing, and viewing radio band interferance in the area.