Cable co. VoIP for small business?

Anyone out there with either good or bad experiences deploying Internet access and/or VoIP services from your local cable TV provider? I’ve read that Comcast, Time Warner, Cox and others are starting to offer attractive bundles for small and mid-sized businesses, but I’ve also read concerns about the reliability of cable VoIP for business, as few providers have yet to achieve the old, “five nines” that the telecos promise (99.999 percent uptime). I’ve got both Comcast and upstart “overbuilder” RCN Communications in my market. But I’m curious about positive and negative experiences with cable service in general, thought I suspect the track records of the big guys would be most relevant.

Thanks in advance.