I went to all cable (phone, TV, internet through Comcast) a bit over a year ago. Have been pleased.
http://forums.pelicanparts.com/showthread.php?t=284482
But you're talking Time Warner, so YMMV.
http://forums.pelicanparts.com/showthread.php?t=326201
The cable modem has an internal battery backup, though we haven't had a power outage to test it with. Internet service has been out twice for an hour or so, IIRC, but phone worked during those periods. I don't think the phone has ever been out. Honestly I'm not that fussed about whether the phone is 99.9% or 99.9999% reliable.
My one complaint is the programming on Comcast. For some reason they seem to think that Portland OR viewers don't need any international channels. Satellite has a far better choice.