Signed up with PIPEX broadband last Wednesday and went live yesterday, two days early. Very impressed with the connection stability and speed. Only slightly negative comment that I can think to make, is that the instalation CD is maybe not as "idiot proof" as say supplied by some ISPs (EG. AOL). IE. a number of things have to be set up by hand. No problem is you have some idea of what you are doing.
I wish they would hurry up and get my "free" upgrade to 1MB sorted out (yeah, yeah, BT are doing it blah blah blah...), because 512kb/s for £23 a month is terrible value for money when compared with the competition.