Nice company, great people, excellent location. Great place to improve technical skills, a great team of developers.
Cons
The company grew with the popularity of instant messaging (especially MSN) and declined when MSN did. The company didn't manage to get enough users on their own new messaging platform (similar to Whatsapp / Viber) and run out of money. The business model was not that great (users first, cash later).
Nice location in the center of Amsterdam. Good team of smart yong and active people. There are lot of fun activities organised by company.
Cons
The main product is still not successful on the market. That means the company is actively trying "to find it self" and sometimes you don't see the clear goals.