Virgin definitely take some beating - our virgin connections (we've had them in three properties now) has always been very very close to 100%

However, a very small minority do seem to have troubles - and that's where Virgin fall apart.

I'd like to give them a beating

They're terrible when something goes wrong IME, that's the best way of putting it I spose. That's made a lot worse when you've been a customer for years

I'd recommend Zen as well if you want a reliable connection and a UK call centre (Rochdale).

However, they are a bit pricey, the 100Gb/month package is around £35 a month on top of line rental. Their cheapest package is £17.99/month inc. VAT and that will get you 10Gb a month. Next package up is £24.99 a month for 50Gb.
Still, you pays your money and takes your choice. If you want a rock solid connection with no traffic shaping and a clear download limit then I think Zen are hard to beat (they even have a Firefox/OS X plugin/widget that tells you how much of your monthly DL limit you have used). Oh yes, and it's only a 1month contract so if you don't like them you aren't tied into a 12/18/24 month deal.

Don't get too excited by ADSL2+ unless you live right next to the exchange (in terms of line length anyway). I was getting 6.4 Mbit/s downloads on ADSL 1 but now only get 5.9 Mbit/s on ADSL2+ as it uses a different frequency range.

Take a look at plusnet http://www.plus.net

Actually bought out by BT a while back but remain largely autonomous and have fantastic uk based support and sales.

I can recommend xilo .. not the cheapest but definitely very very good. On Non-llu exchange during peak hours, never drops below 4.5mb/s. (O2 access often delivered 0.1mb/s).
Also, xilo answer requests within minutes .. really the best customer service i have had with any isp ..

I am not anti O2 for llu exchanges .. in fact I specced 2 BE pro lines at work a while ago and have been very happy with them.

Didge.