Which is the best landline phone service, Cox digital phone or AT&T (formerly BellSouth)?

Where I live our local cable company which is Cox also has digital landline phone service. It works good and everything and it is cheap (about 5 dollars less than AT&T's basic), but the only drawback is that if the power is off for over eight hours the phone goes out and doesn't work. AT&T's landline works well during a power outage, but I don't really trust them because I have had problems with them over charging in the past. I was able to straighten out everything though. I have cell phones, but I don't want to have just depend upon cell phone service.