Pros
Like every other review here, I would agree that the salary and benefits are the best thing about McMaster-Carr. The salary is decent, the health plan is 100% paid for by the company, and the annual bonus is usually 3-5 times your monthly salary. Quick note: although they offer you a "salary," you're actually an hourly employee. Some might view this as a pro because you'll get paid 1.5 times your hourly rate if you work overtime.
Cons
There are literally too many negatives for one review. You will be trained for 1 month to become just a little familiar with their processes and systems (which are all made in-house, so no skills can carry over if you change jobs), but you will be expected to meet their metrics of near 0 mistakes on your first day all the way up until your last. The training is a cursory overview, and not nearly as in-depth as it should be to be successful and meet their metric. Many people fail because the training is inadequate and the DOS based system is complex; nobody who worked here was a slacker. I had multiple managers, and all were annoyed when I asked questions or sought help. If you fail to meet their metric, you will be pulled aside by management and told that your job is in serious jeopardy and that you must pull it together. They won't, however, offer you any additional resources or plans to help you learn why you're failing. They literally think it's easier to fire and hire than to spend time training their current workforce. A lot of the employees have been around for 15-20 years and stay for the benefits; most the of younger employees stay 1-3 years and then leave because the environment is so toxic. I can't imagine what they're turnover rate will be once the older folks retire and McMaster-Carr is forced to rely on younger recruits. If you approach HR and voice your concerns that want to learn and need more resources, they'll refer you to your manager. It's a circle that ends with you gone, either willingly or by being let go. If you're not a kiss-up, don't even bother applying. Favoritism is rampant here, and management is essentially a clique that excludes all other employees (they seriously act like high school kids; it's beyond unprofessional, it's weird.) There are strange rules about everything but no explanation; up until recently, you couldn't even have any drink except water at your desk and no personal effects were to be present (when management from Chicago comes, you'll still be told to put all "unnecessary effects" in your drawer; for me, this meant a jar of pens and a picture of my family.) You will never advance in the company. Management positions go to Management Trainees, people from Ivy League school who have no clue what they're doing. There is no future at this company if you want to grow; you will literally perform data entry your whole "career."