Pros
The pay and benefits are very good for union and non-union alike. Health insurance starts on day one, and they have a plan for just about anyone. From a high deductible HSA plan to a 100% coverage with 0$ deductible plan. The atmosphere is laid back, and it really does take a lot to be fired. If you are ambitious and want to move up, they support you anyway they can. If you are happy being a machine operator, you will still have a fruitful career.
Cons
I don't think a 40 hour per week employee exists. If you work in the union, you find out on Thursday afternoon if you're working that weekend. In the finishing department they only have to give you off 3 days a month. In the retail department they don't have to give you off. If your partner calls in, you have to work a double shift if they can't find anyone to cover for you. If you work in the office, your schedule is fairly laid back, but for most people the workload keeps them busy. There is certainly a lot of money to be made in the company, but be prepared to work for it.