Pros
You really can't beat the benefits. Fully paid healthcare for you and your family. You'll learn a lot and take on big responsibilities which is good for your résumé. The members are awesome and you're working for a great cause. If you're lucky you'll get one of the good managers who respects your work life balance and helps you grow. There are some great genuine people that work here.
Cons
It's almost impossible to get a substantial raise and promotion opportunities are limited. Especially if you're not in the inner circle. Much of the management is out of touch with employees and expects us to drop everything to work a weekend last minute. There's a very high turnover of field staff, and even if you're not field you will have to door knock and participate in all the campaigns. It's a good place to work for a couple years because you'll gain a lot of experience but don't get sucked into staying too long.