My Experience
In my experience, Fasthosts are truly, truly awful.
If we were lucky enough to ever get through on the phone, to chase whatever support reason big or small, every time we were told our unresolved issue had been escalated and we would receive a call back. We always had to chase. We could tell from our machine logs that issues were sitting untouched for days. Even when we got really angry and demanded some level of service, we were left short changed - but the invoices turned up on time.
There was the major connectivity issue that meant customers weren't able to access our dedicated Fasthosts server. We demonstrated it was an issue internal to Fasthosts but it took weeks to get anywhere, no-one cared - but the invoices turned up on time.
There was the hardware issue that screwed up our RAID 0 mirroring which turned our web server into a machine that could respond quicker using quill and ink. It was sidestepped, ignored, brushed over, deflected and never fully fixed - but the invoices turned up on time.
Before it went really wrong - or more precisely, before we actually tested them - at the start we kidded ourselves they were useless at the small stuff but would be there if we needed them. They weren't.
Thinking about how much hassle it would be to move, we kidded ourselves that they failed us once but it was a fluke. It wasn't.
We moved hosting company and have never looked back.
I would never trust Fasthosts with my business or my data again. Ever. And not in a vengeful way, I mean in the same way I wouldn't put my baby in a car seat on sale for £5 because of quality control issues at the factory...