Press over here has published some horror stories re Tiscali, mostly regarding failure to stop collecting payment when service ended IIRC. As I remember them these cases were eventually resolved so that no customer loss arose, if not necessarily to the customers' satisfaction.

Tiscali are one of the bigger players in the ISP market, so if say 0.1 percent of their customers are unhappy then their name will come up more often than Sid's, even if 10 percent of Sid's Corner ISP and Delicatessen customers are furious. My own experience of them as a dial-up provider was a good one, but I cannot speak for their broadband service.

Tiscali Fair Useage Policy doesn't sound unreasonable to me.