The 5GHz work fine, but I have never had any issues with the 2.4GHz and interference from local networks as they are directional and high power, and the 2.4GHz and 5GHz AirGrid units have the same throughput and both use Fast Ethernet (i.e. 10/100 ports).
If you need greater throughput (like 4-5x the N based AirGridM2) and have a real big wallet you can go with the newer AC products that also feature gigabit ports, although gigabit PoE also adds to the cost relative to standard Fast Ethernet PoE, as Gb PoE must be applied at the source and picked up at the destination with center-tapped transformers in the data circuits rather than a simple DC offset.