Avantages
Telecom Experience is vast and you get up to speed quickly. Co-workers are often the saving grace, but it is a cliche. If you are in the right area interaction and exposure with other people/companies that can be good for career advancement.
Inconvénients
There is no concept of work life balance, every so often there will be a push by management towards this, but it lasts only until the next crisis. At my location they constantly cut the work force down and add new projects onto already overworked people. I have been involved in several contracts and can state without a doubt that although they will build resources into the cost to the customer rarely are those actually fulfilled to the teams. RUN...don't walk to the next opportunity!