Vantaggi
The people I've worked with in the office were amazing and helpful, the salary was good for the time, we had some extra time off and some good benefits.
Svantaggi
Our permanently client (E.ON Germany) was detrimental to our wellbeing and its own success. They hired Romanians with data science background to do data engineering, offering no training. Also, they hired people in Germany with random unrelated PhDs to do data science. Everybody was frustrated and stressed out all the time for obvious reasons. I heard things improved in the meantime, but interview with caution and ask many questions, or you might end up feeling mislead. Also the client was the kind of company that treated consultants worse than employees, and we were considered consultants.