Most ISP's can be a pain when things go wrong, and especially when customer services appear to go around in circles (I am having that problem at present with TallkTalk). But Pipex was at one time an highly recommended ISP, and people were leaving BT so as to join them, perhaps shows you how times are changing?.
One thing that I note is the 18 month contract. Quite a number of companies started this, and some have even tried pushing for a 24 month contract. I see now that possibly due to problems and the recession, the 12 month contract is resurfacing as one of the enticers for transferring to another deal or ISP?.