One of the best ISPs around I think, and they just lowered their prices. You get adsl2+ up to 24mbit (10-16mbit are more typical),
with essentially no usage restrictions (30GB/day), and 1.3mbit upload. They also loan you a rather nice wireless/voip router, a Speedtouch 780.
Alternatively, if you want upload they do "Be Pro" annex M adsl2+ with up to 2.5mbit upload, for £22/month - the fastest upload you can get with a domestic ISP. At the cheaper end you get 8mbit for £14/month.
Remember quidco, at £55 it's a nice bonus.
For comparison, the only other genuine unlimited adsl2+ provider out there is Bulldog, and they're 25/month, as well as being extremely incompetent. UKO have moderate limits, but are 25/month also. Sky are cheaper at 10/month if you have satellite TV, but enforce limits and don't offer anywhere near as good a service as the others. Don't even mention Orange, AOL, CPW and co....
ENSURE YOU ARE NOT STILL INSIDE A CONTRACTUAL PERIOD WITH YOUR CURRENT PROVIDER, MOST WILL WANT AT LEAST 1MONTH'S NOTICE TO LEAVE
IF MIGRATING FROM ANOTHER PROVIDER YOU WILL REQUIRE A MAC CODE FROM YOUR CURRENT PROVIDER IF YOU ASK FOR IT AND YOU USE IT STRAIGHT AWAY YOU WILL LIKELY OWE YOUR CURRENT PROVIDER 3WEEKS USAGE FOR A SERVICE YOU CANNOT USE AS BETHERE WILL HAVE TAKEN OVER YOUR SERVICE, I RECOMMEND GETTING A MAC CODE AND USING IT 14-20DAYS AFTER GETTING THE CODE TO AVOID THIS.
THERE IS A 7DAY NOTICE PERIOD TO CANCEL IF YOU DO NOT CANCEL 7DAYS AFTER ORDERING YOU ARE SUBJECT TO THE BE CONTRACT/NOTICE PERIODS ETC.
Edit: seems they have "fair use" limits, but like all ISPs it's kept deliberately vague. Posts on adslguide suggest lots of people have downloaded several 100GB/mth without problems, and I've never heaard of anyone being kicked off or throttled.