Pros
MediaMind (now Sizmek) has a product or partnership for every digital advertising technology need, which makes it a great place to learn about the marketplace and existing solutions. Once you've proved to be a dependable employee, there is an incredible amount of flexibility - unlimited vacation, work from home, time allowed for volunteering. Middle management, generally speaking, is actually very knowledgeable on the offering/products.
Cons
Training for job-based skills such as client services, escalation, sales, etc. is non-existent. Very much a figure it out mentality for everything besides "the platform". Payment is average though the expectations for the pay isn't really fair. Leadership at the executive level is a joke - there is only quarterly communication from the CEO, if that. And basically no communication from other C-Level or country level executives.