Interesting, I have been looking at unifi for some time - but it is quite the investment
I have an EdgeRouter POE and a UAP-lite - might've gotten the cheaper edgerouter if I'd realized the UAP single-pack comes with a power injector. I wouldn't buy the edgerouter POE again, as it uses non-standard passive POE. If I want to be "safe" about the cables I'm running, I'm going to have to buy this device: http://tycononline.com/TP-POE-2456D-24VDC-Passive-POE-IN-to-...
EdgeRouter X + UAP-lite would be around $130.
Not having all the functionality in one device helps a lot as well. Not satisfied with your AP anymore? Buy a new one. No need to change anything about the router and other network infrastructure.