I have been having problems with my Virgin Media 500mbps broadband connection for about a month now. It was installed and working fine for a year prior to that.
Usually at least once per day (often more), the Hub 3.0 seems to reboot itself (the uptime counter gets reset), causing all Ethernet and Wi-Fi connections to drop. This seems more likely to happen in the evening or at night.
I contacted Virgin Media by phone, and a replacement Hub 3.0 (and power supply) was sent out, but the same thing is still happening after replacing the Hub and power supply. I'm sure that everything is plugged in correctly.
I haven't changed or moved any equipment, so I can't think of any reason why this would happen now. I plugged the replacement Hub into a different power socket, but that didn't help. Other devices don't seem to have any issues with mains power.
The power levels were OK before the Hub was swapped, but I couldn't get the 6db Attenuator to fit back on the new hub, so the power levels are a little on the high side.