reply - I use it

I started with Comcast phone - to get the "triple play" - cable, internet and phone when first offered over a year ago here -  I use a C-phone on it all day for a hospital with no problems - same as a regular phone line - and it's unlimited long distance if you need that.  Once in a while if the modems that run the phone/internet (it will be one modem that handles both) have an interruption - you will lose your connection to internet and phone and possibly TV all at same time, but that is very rare  - that will cause your connections/phone to stop working until fixed.  But the savings over regular phone is big, so it is worth it.  I'd talk to anyone in your local area who may have their phone service to see if they are happy with it in general.