Pros
It's very casual, comfortable, and laid back environment. They provide many opportunities to network. Pretty much only permanent staff receive good benefits: healthcare, 401k, tuition reimbursement, etc.
Cons
They do not care about their freelancers and many are very underpaid. They would rather spend their money on stupid petty things, such as parties and paying for EVERYTHING for rising nobody-celebrities, than on compensating their employees. A perfect example: almost taking away our healthcare benefits to switch to a HORRIBLE "healthcare plan." Viacom also do not care much about the MTV Store employees. They get paid very little with no benefits, meanwhile working very hard and sometimes getting out past 2am with no car service back home. College tuition reimbursement may be a pain.