Pros
+Relaxed Environment +Company tries to provide good perks (free lunches, "unlimited" vacations etc.) +Nice colleagues + They are couple of people who are technically proficient, you can actually learn a lot from. But you can number these people in fingers of your one hand and still have fingers to spare. But still good to know these people are there.
Kontras
I worked in the Engineering department, so my comments are about Engineering department. (a) Politics - There is a lot of it. People coming from big companies will be more at ease with this crap, because they got used to it. Others coming from a startup culture will be hit hard by this. (b) Management - I got the feeling Engineering management in OpenX is mostly concerned with hiring. Agreed, there is a lot of hiring to do (see my points below). There is a lot of attrition and they have got a aging platform and they need someone to run like "headless chickens" when stuff goes bad. The management team is not at all proactive. For example it was well known the platform had 'speed' (performance issues). But apart from some proclamations like "speed is important, going forward we should pay attention to this", no concrete actions were taken until two years later competitors were calling out the 'speed' issues of OpenX platform. 2 years! Meanwhile Engineering management was setting up arbitrary SCRUM teams, where most of the employees were bored. One SCRUM team might have lot of work, but another SCRUM team might not. (c) Meetings - If you work in Openx, you will attend lot of meetings. 95% of these meetings can be avoided, instead inexperienced managers call these soul killing meetings destroying everyone's productivity. Middle management is especially guilty of this. A meeting to discuss an issue should be a last resort, not a replacement for work they themselves should be doing. (d) Productivity - Productivity is almost at the bottom. Getting something done is like trying to squeeze water out of a stone. I see several culprits; SCRUM, unnecessary meetings, Attrition, inexperienced managers, new hires, Frequent reorganizations, politics etc. (e) Team reorganizations - There are team reorganizations roughly every 8 months. Some of these are forced by people leaving. Other are done in the name of "Velocity", this almost always have the opposite effect. I have met several employees, who are numb after going through several of these reorganizations. In a 3 year stay in OpenX, expect to have about 4 or 5 managers. (f) Lack of enough work - Most of the employees are doing mind numbing rote work. This is despite the platform starting to show its age ( see my reference to speed above). The Engineering management have failed to proactively form teams to attack the problems. They still want to hire more people, so they have people on standby to pour water when fires break out, which they often do. (g) Zombie culture - There are lot of zombies in OpenX. These are people who are in OpenX not because they think the work is great or Compensation is great. They are there because it affords them a life style they want to have (Some live close to the office, others makes use of flexible time to support family). There is nothing wrong with people choosing to work at a less than challenging work place. We all have bills to pay, kids to raise; right? But be aware they are there. Amusingly one of my colleagues referred to these Zombies as "vesting and resting" department. So if you are looking to find employment here, my advice is to do well in interview. Then negotiate the compensation (base salary) to a level that would force OpenX to give you challenging work. Remember to figure all the above points to your asking base salary, so if worse comes to worst you at-least are well compensated and feel a little less guilty about wasting your 18 months in OpenX.