Very prestigious company, terrific location... much depends on who you work for and when
Pros
If you work at NBC News you will find your experience depends largely on when you work here and the department you work on. I worked in several producer roles, which I generally enjoyed. Like most anywhere else each department has its own kind of sub-culture depending on the type of people involved with it. You can work with some really interesting and smart people and develop skills that can last a lifetime, in addition to beefing up your resume. 30 Rock is a great place to come to work everyday. If you work for the popular morning shows it can be a fabulous experience as you work in a glamorous setting and meet many celebrities and famous people. The evening shows like Nightly and also MSNBC are more hard news oriented. Compensation depends on which department you work in. Many entry-level roles don't pay that great but you'll get good experience. If you land a more experienced position you will get good pay and have great benefits. If you network enough you will have a good chance of working in the news business a long time and making good money as people will give you a referral.
Cons
The news business is relentless so work-life balance can suffer. Sometimes people are forced to work very long hours and have to cancel pre-planned holidays on short notice to work when news breaks. This is especially true for the anchors and anyone involved directly with the news production. It's not easy to land FT staff roles, and there are lot of freelancers, some who move up but many who don't. Landing a FT role is almost totally dependent on you're ability to network and develop good relationships. If you just apply for a position online without really knowing anyone here your chance of landing an interview is practically zero. It's a very politically liberal and feminized work environment overall, so if you don't blend in well with the liberal culture at NBC that can be a challenge. In general management expects everyone to pull their own weight at all times and aren't very receptive to employee's personal needs or concerns, unless you're on very good terms with them.