Pros
Free parking; flexibility in work hours; on-site cafeteria. Proximity to metro and 495 makes working at HQs convenient.
Cons
Despicable treatment of employees in Corporate HQs. Routinely made to work nights and weekends with no notice which was not disclosed during the hiring process (I was salaried and therefore was not paid or given comp time). There is a pervasive culture of 'crap rolls downhill' that has been in place for many, many years and to which the c-level team wholeheartedly believes in. This results in a hostile work atmosphere to which HR blindly turns its head even when reports are made involving demeaning, threatening behavior by higher level executives. In addition, be prepared to work holidays even as a higher-level employee.