Pros
Pay and benefits are nice, frequent breaks (every 2 hours if working a 12 hour shift), paid lunch/breaks, sick pay and personal holidays, safety is drilled into employee's heads, highly trained ERT (Emergency Response Team), and good security.
Cons
Management is "Superior" to all, as in they are holier than art thou. Hated working under the plant manager who was present during my employment in 2012-2015 and HR went to crap. They will walk you out of the plant/fire you over the dumbest things (even for so much as uttering a curse word), they've taken away profit sharing, forced 401K of 6% or you can't have it, and it felt like they quit fighting for decent priced insurance. Also, no pension. You put into your 401K or nothing when you retire. 3M has scaled way back on bonuses offered to employees and hires/shuffles around horrible management. You can almost guarantee whoever your supervisor is has no clue what the actual job is of those they are supervising, as in they've never done the job so you could lie and say something takes you twice the time to screw around or you could say it takes half the time and do a really crappy job. If you don't do your work, management will more than likely just force one of your co-workers to do it (one of the grunt workers) because none of them have a spine to speak to those who defy them. You must also have a certain last name to gain any recognition to move up. If your nose isn't brown, you can stay the low man on the totem pole. Also HR isn't there for employees; they're there for "the company" so they do no wrong because it's the "employees".