I've had a Virgin SuperHub 2 for about a year now and it's been fine.
I don't use Ethernet, but use dual-concurrent WiFi for 6 devices, 3 of which use 5GHz. My primary computer connects at 75Mbps downstream / 5 Mbps upstream which is Virgin's cheapest option and is certainly fast enough for my purposes.
I haven't noticed the computer slowing down, although my back-up is rather a slow HP TouchSmart, which has rather a poor internal 2.4GHz only WiFi card, so is connected using a NetGear 5GHz adapter.