Pros
Overall it's a great working environment. You are literally working at the world famous 30 Rockefeller Plaza, which is definitely a perk in itself. For the most part everyone here is very friendly, managers are on your side and want to see you succeed and climb the corporate ladder. You can definitely advance and continue to grow as long as you demonstrate you're a hard and motivated employee.
Cons
Unless you end up in the exact field or department you want to be in, moving around and advancing to another area is actually difficult despite being in the company already. In order to make a switch or jump to a different department be prepared to know someone (however I guess that goes for any type of job or company really...). Unfortunately, HR only does so much and submitting internal applications doesn't mean they will look at your resume at all. I've applied to a few different jobs in different areas from where I work and unless you know someone and can track down the specific hiring manager, chances are it won't be seen. There are some difficult people to work with, but that goes for any company really. Working in the news department often means working odd hours and on the weekends, however this is kind of expected and I can't hold it against NBC, however scheduling can definitely be more thought out and considerate of people's lives outside of work.