Pros
Pension and free lunch are great. The company has never laid off an employee for so long so the feeling of stability is there - which is a plus in the current shaky economy. It's business is doing great. People in charge of running the business side must be smart and competent.
Cons
This pertains to the I.S. division only. Promotion is not consistent among different groups at Northwestern Mutual especially in I.S. So its easy to get discouraged. Performance ratings are inconsistent among managers and among IS specialties yet everyone is using the same grade system to determine pay. There's a lot more value to soft skills at NM than in technical skills as shown by the people who have advanced in the company. So if you're a technical person this may not be the place to work for. This is a place where a lot of talking needs to occur before something can happen.