Pros
Dynamic, global company that is a leader in its space. Incredibly transparent communications from many of the senior managers via email (unheard of in a company of this size). CEO and CFO do a fantastic job of explaining company strategy at quarterly company meetings and answer honestly when asked tough questions (I've never seen a CEO be so honest - very cool). Great physical work space. Smart, nice people who don't expect you to give up your personal life (good work/life balance). Opportunities to work on global projects. Company does a good job of making work fun (almost monthly activities for employees, and managers have freedom to recognize their teams with some small budget set aside for recognition).
Cons
Pace of change (reorganizations, shifting or last minute priorities) will drive a lot of people to frustration or ambivalence. You expect a company of this size to have its act together - leaders who lay out a vision, know how to focus a team on what's most important...but that's not how it is here with most leaders. You get frustrated because you don't have time to do it right, because your leader doesn't seem to say no to protect your limited bandwidth to ensure you get the key things finished. There's too much of a short term focus.