
No, there aren't any reliable providers left in the UK market and there won't be for so long as people want massive speeds for virtually no cost.
Reliable infrastructure and the people to keep it reliable are not cheap. Peering bandwidth is (generally) not cheap - yes, I know there are some reciprocal peering agreements but they're becoming less and less common now as cash-strapped providers look for some way to pay for the infrastructure the users are unwilling to pay for.
If you honestly think you can get a reliable 100Mb/sec downstream connection with no caps/throttling or limitations for the prices currently offered by Virgin then you are, quite honestly, delusional. EVERY ISP is recognizing the fact that bandwidth demand is far exceeding the cost users are willing to pay, hence the introduction of fair use policies, caps, throttling and more.
Until people are willing to pay for decent, reliable service it just won't exist - it's not economically viable.