The broadband is perfectly fine.
Their support is awful.
When I first signed up, it was a complete nightmare to get their router which meant I was without broadband for a few days. It got lost, and they wouldn't send another, despite several calls - "computer says no" kind of mentality. Rather frustrating.
Having had 18 months or so of stable broadband, I then made the mistake of upgrading. This came with a new router. Sadly it was not a case of simply swapping it out. For some inexplicable reason, this required them to make some configuration changes on their end - which they seemed completely incapable of doing. It took them 3 days (all without working broadband) and several calls, before it was finally sorted.
The price, at £20pm for 70mbps, is the reason I'll stay.