I have been with Fasthosts for over 4 years, now as relunctant customer but have not used my site for over the last 2 years because of unreliability. It's also really slow, and their control panel doesn't work half the time due to server timeouts - incidentally, I never have problems (of this degree) with other websites, so it's not my connection!

Customer services are really bad, they continue trying to bill you even though you cancel. They bill for the whole year upfront without invoicing you, so you don't know what hits you until it hits you.
They now will not allow me to close my account until I pay for my service from July 2008-July 2009(!). But if I hand over my new credit card details I'll be billed for the next 4 years, like other customers. If I don't they have threatened to chased up debt and incur fees. They won't let me close the account until I pay up for 2009. If I do, then they won't let me close it until renewal time next time. Absurd!

In summary, they're great so long as you don't want to leave them or want a reliable or quick hosting service. If you do want to leave them, expect to be chased up for payment for the next few years!
If you want an unreliable webhosting service with really bad customer services who don't give a damn about you, which you will have to keep paying for until the day you die, then this Fasthost are a great company for you and will fit the bill perfectly.