Pros
3M hires experienced professionals, I worked with high qualified colleagues and managers who are super supportive and professional. Company culture respects individuals' unique and encourage employees to speak up. Integrity and leadership are the top values. The first week in 3M was not easy for me because company requires you to work immediately with the mindset of "learning on job", you need to be prompt in your actions. Accuracy might not be necessary in some cases as you are given the chance to make mistake, but make sure you learn from the mistake and don't repeat it in the future. If you like can work under high pressure and want to learn fast, a fast-paced working environment like 3M is a great place.
Cons
3M is big company with many products' community, the whole system is a bit complicated.