Pros
The people to work with are the best. Each and everyone of them is enjoyable to work with. The afterwork activities (most of them 'just happen') are a big bonus for this company. Even though the average age of the employers is low, there are a lot of very capable people to learn from.
Cons
The work, a lot of the newer processes and detailled timetracking don't stimulate ownership over projects. There isn't a lot of variation in the work as a developer and it is really difficult to explore new things if it isn't directly billable on a client. But the worst thing of all is the base salary for engineers. In comparison with other companies, it is below average. Especially since a lot of the employees really go the extra mile to make the magic happen. Also, the flexible hours are not that flexible and don't allow working from home, but that is a minor issue to me.