Pros
3M plants are usually the best paying jobs in their area, which is how they keep employees in spite of all the abuse.
Cons
Prior to 3M ownership, our plant had straight shifts, sick time, bonuses for perfect attendance, and very little mandatory overtime. Now we work rotating 12 hour shifts that make family life difficult, employees are forced to use vacation time when sick (3M will deny this but the system is so rigged that it is vitually impossible to call in sick without accruing disciplinary points - your doctor has to fill out a mountain of paperwork verifying that you could not perform your job duties and if submitted in time, is hardly ever approved), time in and time out has no flexibility making communication difficult and staff was cut, overtime is not only built into the schedule but demanded regularly as well as working holidays, and you must also burn up vacation to take off on a holiday. 3M claims to have a week of "Other Paid Absences" which looks good in theory but again employees are given disciplinary points so it's a dangling carrot. Nearly weekly reminders that you must make another sacrifice for "The Big 3M". Opportunity for promotions is laid out in theory, but impossible to achieve - the "certification tests" for promotion do not exist. In summary, 3M is a good place to make money but throw away your life, family, and self-dignity.