Pros
My experience at Unum has been great. They have paid for school, benefits are good, salary is extremely competitive, and I have received numerous opportunities for growth in my career. After working for several other employers I finally came to Unum due to the recommendation of several friends. Of course all jobs have their bad days and no employer is perfect, but overall I have been extremely impressed with management and have been treated very well.
Cons
As others have mentioned, your experience is directly affected by your department and the type of work you do. Be sure to evaluate the work carefully when interviewing and don't hesitate to ask specific questions before accepting a position (ask what a typical day looks like, what the department goals are, if there are production requirements, etc). There are many positions with unfamiliar names, so if you don't ask you may not be 100% sure what your job will look like. Also, this is a LARGE company. I have worked for both large and small companies and I enjoy the hustle and bustle of large corporations. If you prefer a small company this may not be a good fit for you.