I've been a Virgin fibre (50mbs) user for over 4 years. Since last august, playing Quake Live at peak times has been pretty much impossible with lots of packet loss and fluctuating pings. Normally I would ping 17-21 to UK servers, at peak times this would be 32+ with spikes and packet loss.
I'm just in the process of switching to BT infinity (40mbs). Can any of the Virgin and Infinity fibre users let me know what you think to your service? Ping times etc. Cheers