AirOS and everybody else has WDS these days, Mesh is different that uses AD-HOC mode(check meraki.com, google olsr, 802.11s etc). Routerboard is actually also great hardware vendor, and cheap too. However it's not in US, and it sells licenses with its software with a premium, which is not attractive to customers, esp those in other developing countries. UBNT wins the battle easily with great hardware, and most importantly, free software going with it.