Pros
I had the pleasure of working with some great co-workers, colleagues, and managers in the specific division I worked in. Our specific office also tried its best to bring the culture to the 21st century, but could only go so far.
Cons
Culture, IT infrastructure, offices practices, and procedures are all outdated. When you walk into the headquarters of Mason, OH, prepare for an incredibly stale and 1990's corporate environment with the "business professional" dress code (suits and ties on men, blazers on women), old tan cubicles, and dry personalities. Luckily I was in the Chicago office where things tended to a LITTLE more casual, but always seemed as if our office was pushing the limits of being able to take the workplace to the 21st century. Working from home was basically unheard of, and IT was not prepared during the pandemic to let employees work remotely properly. They also force you to use Internet Explorer as your main browser. Egos also tend to run rampant in some departments/roles. This is definitely a "sip the kool-aid" type of company where employees get sucked in to thinking Cintas is the greatest because they're comfortable in their role and get handed these shiny "awards" for their hard work that are completely irrelevant to anywhere outside of the company.