Pros
The brand-new new product, Qlik Sense, is one of the top if not the best data analysis product out there. R&D has done a phenomenal job in creating something beautiful, easy to use, and useful. Qlik should be proud of what it has accomplished - re-revolutionize the BI industry once again. The challenge is still around increasing market awareness. Qlik has been around for 20 years but Tableau has recently taken the lead in awareness. Qlik is well-positioned to take that back with proper marketing and customer nurturing. Tons of career opportunities if you know how to network across the company. People change roles frequently and it's not discouraged.
Cons
The company has grown so fast (head count doubles every few years) in so many locations (Philadelphia, San Francisco, Raleigh, London, Sweden, Singapore, etc) that it's gotten very difficult to keep track of who's doing what and has resulted in duplication of effort or lack of alignment. These challenges can certainly be overcome but be aware of what type of environment YOU thrive in. Some people love the far-flung international culture, others don't fit.