I have BT infinity for internet and telephone and it is flawless. I don't use the television services, so I can't comment on them. I hear good things though.
BT's Homehub has been voted best service provider router more than once.
My partner has Virgin for telephone, internet and TV and while the TV and internet are pretty good, though not as fast as BT, they are very reliable.
The telephone has been terrible lately with lots of loss of service. The problems have taken days to fix, so if you need a reliable telephone, I would stick with BT.