Pros
The compensation and benefits at Unum are top-notch as many other reviewers have reported. However, I've found that it is the people at Unum (managers or otherwise) that make the experience at Unum great. The people I've met thus far are well grounded in reality. They will not forget that you are a person and not a machine. The Paid Time Off is incredible and the work environment is busy but supportive. It is easy to make friends, laugh with coworkers and still be productive.
Cons
Not all organizations within Unum are constantly advancing or coming up with innovative ideas. However, an insurance company does not need to be a cutting edge technology company. Projects may take longer than they should to complete in some organizations because there are many day-to-day tasks that trump special projects. This really isn't a con because there are parts of the business that just need to work. But if you are looking for rapid innovation don't join sectors that are about the day-to-day grind. Look for groups at Unum that develop strategy.