Pros
You will work with very good people, from which you can learn a lot. Additionally, for example as a dev, you will have people with concentration on big data, UX and devOps around, which will give you another perspective on things and directions to evolve. You can freely chose the kind of formation you would like, also if it is not necessary for your current job. A nice place for curious people who want to keep moving.
Cons
not really a lot to mention here. As I worked there the company was fast growing and they had issues to keep up with the structure and communication. But a normal process I guess.