Pros
Good ideas. Sensible business model, however it can be slow for new business. Possibly ahead of the market with this client-facing model which may mean they cannot wait for the market. The one major client is an amazing advertiser to have and means there is great potential if just a few more major global clients can be found. Growth could be huge if company can last. Platform does a great job - largely due to the people using it daily to deliver campaigns. Many good people helping drive the business forward (though a number have left). In all teams there are really great staff with great skills and fantastic ideas.
Cons
Summed up by the reaction to poor reviews on Glassdoor - senior staff were told to post positive reviews. Don't address the problem; shout over it instead! (Easy to spot those reviews. One current employee posting a negative review was hunted by management...) Having only one client doesn't make for a dynamic workplace. Not great opportunities for career progression and experience. Incredibly slow at any dev work, product work and integrations. Constantly changing priorities and rarely communicated internally, The engineers are good, its the senior management who cause problems. The Peter Principle often seen in action, and ignored by management until too late, especially with many managers lacking experience, people skills or training. Loss of key staff is seeing any office outside Bellevue HQ shrink and lose further staff. Lack of any focus on culture or morale makes a decline inevitable. AudienceScience sucks the positivity out of people and leaves a lethargic staff. All the hallmarks of a sinking ship right now. If the one advertiser leaves, then it's over. Many, many staff have left. As someone mentioned, this includes CRO, SVP, VPs, many Directors, Account Managers, Engineers, Product team and others - never a good sign.