Liars, Damn' Liars and ISPs
Virgin's "traffic shaping" and their little caveats throughout their small print means that you'll NEVER get anything approaching their quoted speeds. You might get (very) short bursts of high speed - if you're lucky. Virgin also sell all your browsing data to advertising companies.
BT (if you pay for their most expensive VDSL service and are in a covered area) don't cap or restrict their service too much (I get an absolutely consistent 78 Mb/s down, 17.8 Mb/s up), but their DNS lookups are restricted (supposedly due to some Act of Parliament).
Talk Talk are exactly what they claim to be - all Talk! They cannot deliver any kind of useful service at my Central London address, and my neighbours - on a different telephone exchange - get data rates that I used to get from a dial-up modem! They are incompetent and dissembling.
Most ISPs are just reselling BT services, so they're all as bad as each other, and Virgin are a clueless, useless, sad joke. You'd think that Virgin - as a monopoly on cable services in the UK - would make sufficient effort that their service would be several times better than anything down twisted copper wires, so that they could take over the whole market - after all, the theoretical bandwidth down a coaxial cable is spectacular. Virgin just use their position to fleece their customers for an abysmal, intermittent "service".
There doesn't appear to be ANY ISP in the UK that can provide a proper, fast, stable, uncapped, unrestricted service at any price. Please correct me if I'm wrong!