Pros
Great people, great environment, interesting or at least not-boring content, opportunity for lots of responsibility, a great place for creative minds, like production boot camp. You will not find such a high concentration of co-workers so fun and creative anywhere else. MTV Holiday Party is epic. There is a large social scene at MTV and your co-workers will become your life. Stay 3 or 4 years and you'll probably wanna get out... Though it was probably the most fun 3 or 4 years of your life. Oh, the stories you'll tell.
Cons
Long hours, often incompetent management, almost zero benefits for permalancers, while you may be friends with everybody you have the feeling of being replaceable at all times and do not feel valued as an employee, often trivial content without much interest shown towards more substantial programming, poor job security, never enough staff, sometimes there are obnoxious co-workers who think they are still in a frathouse or going to end up famous on TV, unwilling to put more money towards the production side versus the business departments. budgetcuts/downsizing all the time... why jump on board a sinking ship? on the production side anyway.