Vantaggi
You could coast by for years with mediocrity and status quo (pro or con). Very friendly people. Lots of resources to use for projects (if allotted) but many other perks of having a lot of people in a company. 401k matching and stable stock.
Svantaggi
Cycle of revolving upper management creates a layer of management that focuses more on short term gains that make their numbers look good. Hard workers usually get more work as others on the team ride on the coat-tails to be able to put results on performance reviews. Management usually doesn't know better as communication is not active between management. Lots of 15+years at 3M'ers who are on the status quo coast to retirement. Seems to still be a good ol boys club. Large age gap between management and rank and file which may be due to many hiring freezes in the 90's/2000's and continual push to reduce operational costs.