Pros
Work Life balance is good in most areas. Retirement benefits are great, you get 401K and a pension. Onsite fitness center. Other benefits are OK. The people you work with are generally top notch, teams have a family feel. Some employees can work from home or remote.
Cons
If you work in a SCBU you'll have to deal with political infighting among the various business units. Once you reach a "senior" level in your position opportunities for advancement are slim to non existent if you don't have direct reports. Its not uncommon for senior staff level employees to retire having spent the previous 20 years with the same job title. At times work-life balance can tilt heavily towards work. Salary is on the high side of mediocre, other companies will pay more but Principal tries to make up for it with a flexible work environment. Another drawback is that during the remodeling some employees will get crammed into building with very little amenities.