Ubiquiti builds some neat stuff, I have to tell you. I have a couple of their products. Unique, compatible, powerful, simple to use. But full-featured 802.11 radios, compliant with the various 802.11 amendments that live in the 700 and 900 MHz bands? What? "Based on 802.11g OFDM" the specs say. Take note of the 600 mW output power on that 700 mW radio. Yikes!
I hadn't really considered this type of thing until a CWNE friend of mine started checking out some new mesh products. He asked me about the positives and negatives of such a thing, and the first thing I thought of was interoperability and analysis. The Wi-Fi Alliance is only interoperability testing and certifying equipment operating in 2.4 and 5 GHz. So, 700 MHz (public safety), 4.9 GHz (public safety), and 900 MHz (ISM) is kind of left out in the cold for now. Additionally, analyzer vendors don't make drivers for cards that work in non-Wi-Fi bands, so site surveying, protocol analysis, and spectrum analysis is out. That would mean you'd be flying blind. No thanks. Been there, done that.