Pros
The overall environment of Penn State is excellent. The university tends to feel like a community working together to produce high-quality education, and this is a good feeling. If you are working in the right department/position you can have a big impact on the tens of thousands of students or thousands of employees. Job security is high if you hold a full-time standing position. Resources available to faculty and staff are vast: excellent libraries, gyms/workout facilities, special interest or hobby clubs, intramural sports or spectating at any of the varsity sports, concerts and shows on campus, and more. The area surrounding the university includes several state parks, gamelands, trails for hiking and biking, hunting/fishing/etc. Cost of living in the area is fairly low. Every department is different in terms of amount of work, stress level, pay, coworkers, etc. so it's hard to comment on many specifics related to employment.
Cons
The university is generally well-staffed and in some departments, over-staffed. This can lead to some really slow days and a lot of dead wood occupying offices and cubicles to collect paychecks while others pick up the work. Once I learned my job, I didn't have much opportunity for new challenges, and I see this all around me in central IT. The org chart is difficult to navigate. If you are ambitious and want better opportunities and better pay, you need to apply to new jobs within PSU because promotions are not given. Old-fashioned silo hierarchies breed bureaucracy, squelch good and creative ideas from the worker bees, and cause tension in inter-departmental communications.