Cablevision is first class, and well known for that fact. They're THE BEST in the industry. I was so excited when I heard it. James Dolan and Bill Bresnan were friends - both old-time New York cable guys, and my understanding is that Dolan's purchase of Bresnan was more of a friend thing than a money thing. Granted, Dolan sees it as a good investment. But it was a friend's business.
Cablevision is known for high speeds, excellent customer service, and top-notch all around service. No, I don't work for either company. Some of the companies bidding on Bresnan were not. We got REALLY lucky. Good things are coming
Now, as for why Bresnan sold - simple - the family wanted out. Bresnan Communications was Bill's pet project. He died, the estate got out. Simple.