While I really dislike Time-Warner Cable, I really hate Comcast. Why would they be good together? They'd have monopoly security.
They've got agreements with municipalities for exclusivity from other cable companies. This is the way it has been since the early days of Cable TV. They had to pay to wire the area, so they wanted a captive audience. In some cases, they've made sure that homeowners' associations would have a no-antenna rule, so that you couldn't have off-the-air programming in your fancy schmanzy development. Thankfully, that didn't stop using DirecTV or Dish Network.
I've got through the various local cable companies and many have been personable and reliable. There was only one, American Cablecom, which handled the Audubon, PA apartment complex where I lived, surrounded by a large cable company, that things weren't good. The company had a 28 day repair clause. If a channel was down for more than 28 days, they would have to give credits. They would certainly show up on the 27th or 28th day each time.
When I lived in Altamonte Springs, FL, the tiny cable company was so bad that people in the apartment complex were hoping that Time-Warner would buy the company. They did, and service became somewhat better, and Time-Warner's marketing people showed us that they were nasty, vicious, and deceitful. Besides that, there was never a problem with service--it was all in "your set". When they sold the area to Bright House Networks, nothing changed but billing since the same local people were in charge. I swore I'd never have another bout with Cable TV.
Back when I lived in the Philadelphia, PA area, I was lucky enough to avoid Comcast. People hated Comcast. People hated to call Comcast, if there was a problem. You've heard that Philadelphia is one of the rudest cities in the U.S.A.? It can be. I swear that the people working for SEPTA (transportation authority) and Comcast are the worst ever, and I know how to swear very well. :-D
When I moved to my current location, Comcast had bought the smaller cable company that bought the local cable company. My adoptive mum was on the phone constantly as things did not work. It wasn't their problem. Toward the end, she would try to change channels, and in 3-5 minutes, the channel would be changed. The service technicians swapped the equipment 3 times and there was no change. At least, she didn't have to have someone yelling on the phone that the problem was in her set.
Now, with all that blah blah blah, does any customer really want Comcast and Time-Warner to become one huge entity? More than ever, I'm thankful for DirecTV.