Re: Virgin Media customer here.
We were using a separate router, until we hit a bug with the (notso)Superhub which caused our connection to drop every few hours, so we're back with the (notso)Superhub, and it's 'quirks', like "Wifi passwords must contain exactly two numbers. One is too few. Three is too many, Four is right out" etc.
We seem to have a pretty good speed though, but it's hard to tell where a problem might be, if (eg) iPlayer is stuttering, is that the BBC's problem, or just the internet at large, or VM's network, or our connection to VM's network? Mostly it's just bloody fast though.