Pros
AARP's mission is a shining north star. As a career move, you will be happiest if you work there for a very short time for the experience, then leave.
Cons
The company lacks appropriate focus to execute on that mission. Focus on what you do well. Eliminate slow management structure. Look around at the world as it is and change what you are doing before you lose all relevance to GenX and future generations. There is no way for employees to get promoted. Management does not see the value in current employees. Instead, they always look for the next great person or thing. This does not engender a strong internal culture; instead, mid-level managers are all fighting over territory and employees are keeping their heads down and trying not to get noticed so they won't get caught in the crossfire.