I've never had a problem with it, despite me harboring ill feelings towards communicastcast's cable tv (kept the internet, got directv for video). In this area, it's 20 meg burstable (I think some areas are now 50 meg burstable). All of my previous facilities used comcast. Right now I use comcast as the backup link for the stations (the router sets the routing cost higher for comcast, so if the primary ever fails, it automatically reroutes through comcast).
But with fios being available, I think fios would be a better choice all around for the speed/price. I just don't have any experience with their reliability.
73 de KB3OOJ