Pros
I have worked for McMaster-Carr for 3 years now. I started as a business operations specialist in the phone contact center, and then moved departments to Sales Operations/Order Support. McMaster is a great company to work for. I love the standard 40 hours a week and no work at home philosophy. The work life balance is important to me after working in retail for several years. I also think the company hires a lot of smart people which keeps the company running and making decisions with how to evolve our business. They have outstanding benefits including fully paid health care for you and your spouse, cash profit sharing which can come out to several extra months salary, and a very generous retirement fund that they contribute to without requiring you to match. Apart from the benefits, McMaster-Carr provides an environment for you to learn and grow. One thing to note is that employees tend to move laterally across departments. Unless you are hired into the management track, you should expect to do good work and even move departments over time, but vertical promotions are limited. I've really enjoyed moving to a new department as its helped me to learn another angle of the business. If you want a stable company that actually demonstrates they care for you in the benefits it provides, rather than rhetoric from managers making empty promises, then come work here. I've noticed several negative reviews on this website and I suspect many of them are from ex-employee who were let go or were not a good fit. You are expected to perform here, so you can't expect to keep your job forever if you're not willing to put in the work.
Cons
The largest con for me was the limited opportunities for promotion. Work across most department is dictated by the demands of our customers and therefore you have to be able to handle a high volume of customer interactions/transactions per day.