Pros: free lunch 3 times a week, nice office space
Cons: political exec team, moving target of overall strategy
In my time at OpenX, I've observed some very disarming staff "departures". While some of these exits may be employee desired, a fair number have been sudden, politically determined, and horribly executed (no pun intended). To see several colleagues fall (or be pushed) from grace has been humiliating and extremely stress-inducing. For me, OpenX fundamentally demonstrates its lack of stability within the company due to the senior team's turnover rate — not to mention poor character among the executive team. And that is why the rating I give it is so low. If relative job-safety is important to you, consider this warning.
Furthermore, there is weakness from the top down. The CEO wrote a LinkedIn article in 2013 speaking exclusively of the need to tell people of their weaknesses without once mentioning what a manager could and should do to help an employee overcome those deficits and grow both professionally and personally. He's essentially saying that all a coach needs to do is tell a player to throw the ball more often, when what's required is a much deeper discussion about strategy and timing and recognizing opportunities and calculating risks. He's viewing the relationship purely from his own needs (get something done) instead of his employee's needs (learn how to do something). I don't think I could, in good conscience, call him a leader.
NB: It's important to note that all the "good" reviews are done in a cluster in early 2013. That's no coincidence as there was an small, short-lived internal push to produce some positive reviews about working at OpenX so as to improve its image. Do take those reviews with a grain of salt.