Pros
I think I've never learned so much in such a short period of time. Lessons that I will keep with me for the rest of my career. The clients I worked with were challenging in a good way. In general, super nice colleagues and as other comments here state; great and generous after-work parties. The salary was competetive.
Cons
Even though the colleagues are generally nice, there are some people (including management) that talk badly behind people's backs. This gave me a sense of insecurity. If you're not a "drop me in the ocean and learn how to swim"-kind of person - look elsewhere. The positives that come from it are that you learn a lot and fast. But the majority of my time at Avaus, I suffered from an excessive amount of stress due to a high workload. Unfortunately, I also experienced projects that provided the customer no value what so ever and I felt uncomfortable in taking part in them.