For me it was a very fruitful cooperation, benefiting from a lot of telecom knowledge.
Pros
I would say the total professionalism involved in every aspect of the job. An outstanding work ethic and environment to work in. Excellent place to grow and develop your skills for a great telecom career
Cons
One downside, from my point of view, could of been the lack of, sometimes, interesting tasks, if I can summarize it like that. Another one would be the use of Kanban, but again this is a subjective point of view, meaning that though given a task most of the cases you could see it through. Other would be the inappropriate time schedule of certain training courses meaning you would take the course and practically, start to effectively work with that knowledge many months after that, affecting this way the yield of the work process.