Pros
The benefits at 3M are top-notch. Salary, medical, and the 401k match are very competitive. 3M also offers a lot of development opportunities such as trainings, travel opportunities, and forums. Management is very flexible (usually) when it comes to working from home or alternative work schedules. You can really make your career your own and have many avenues and career paths to explore.
Cons
Although most benefits are great, 3M is behind other companies in PTO. You have to work at 3M for 4 years to receive 3 weeks of vacations, before that you have 2 weeks and a handful of personal days. It seems like this is an inflexible, non-negotiable policy. 3M is still struggling with a stuffy, conservative culture as well. This culture is perpetuated by top level management.