Pros
I worked for a channel within MTV Networks for more than ten years. It was a great experience for the first four - lots of energy, lots of talented people, and a great learning experience. They offer solid benefits, 401K and all that, which is great.
Cons
The company line is that "creative is king" but in practice, the only thing that counts are numbers. So they've created an environment where everyone "manages up" and there's not a lot of loyalty. It's a huge company, so obviously this is not necessarily true across all channels or departments, but there is a lot of general dissatisfaction among employees especially in creative departments. I always felt sad watching new PAs come in full of enthusiasm only to be crushed and disillusioned within a year.