The only thing keeping me from the Unifi products is the need for a central controller. I don't want my WiFi depending on my desktop computer being alive, nor do I want my WiFi depending on some remote cloud service being alive / reachable.

The inevitable alternative, I suppose, is some sort of dual-NIC fanless PC contraption running the firewall, NAT, and all of that. My concern with that is, while it's super flexible and configurable, it's also something that requires care and feeding, versus something like the Google OnHub which just magically updates itself.