I had Cox for 3 years when I lived in South County. I now have AT&T in Corona, which I've had for 6 months. They're the only outfit where I live. I think Time Warner is starting to move in, but they're horrible.
Overall service is good, haven't had any problems with my internet or TV. I think CUSTOMER service is horrible though. I do think Cox is cheaper, and I miss the little things, like being able to have the radio stations on my TVs (AT&T only offers Urge, which blows). AT&T overcharges for their router (but it does have built-in WiFi which is handy) and DVR boxes. I pay around $136 for UVerse, which includes phone, cable, and internet. I was able to get a package for a year that gives me free internet; otherwise it would cost $45. I also get free Showtime for a year.
If Cox comes to Riverside County, I would drop Uverse in a heartbeat.