Purchased one to replace my second failed BT Home Hub 2. What a change. Instead of flaky connection at 150 Mbps, I now have solid 300 Mbps Wifi across my entire house. And its never dropped yet. The setup was done in about 2 mins flat. Sure, it's ugly compared to some routers but what you want is it to work. The only drama I had was assigning a fixed IP to a device on my network. Seems somewhat difficult for no particular reason (you have to copy and paste a MAC address from the DHCP allocation table. In other routers you just click and select the IP you want). That said it does work when you've set it up.
2 week update
Since installing this router I have noted the broadband speed has gone up from 3 Mbps with the BT HomeHub 2 to 5 Mbps with the Billion. BT really are peddling some crap kit. Never again.
4 month update
Unbelieveable. It just works. Never a dropped connection, never a stutter. Speed has crept up another meg too! It is what technology should be...fast, reliable and better than expected. I wish my Dyson vac was like that....instead its slow, broken and crap!
1 year update
Still solid. The latest firmware update 1.06d was easily done and adds IPv6. The system has beautifully mated up to a Synology and I shall be getting another one of these to replace my Dad's crap BT home hub.