Pros
Many people work from home full-time. Lots of varied environments to support, which really teaches you a lot of different IT perspectives, and really trains you to be able to switch gears and multi-task. Some very talented individuals work here so there is often a wealth of knowledge to be learned, and a lot of experience to be gained. While the company does not have a lot of brand-recognition, its customers are often very well-known. Company has beefed up their mobile phone support, it is now quite good. Decent benefits, not great, but not horrible. I believe their about to switch from Cigna to Aetna so things may change. Atos has also made some very good and interesting acquisitions in the last year and a half that have really grown it's business in terms of size and scope/breadth.
Cons
Unless you are a major slacker, you are probably going to be horribly overworked. Company works really hard to outsource everything. If a US customer does not want to be outsourced (India), then they'll bring in engineers from South America on a work visa. They work as hard as they possibly can to avoid promoting from within, or hiring talented US-based engineers. In addition to no promotions, there are no raises and no bonuses, even if you max our your performance review. Can be slow on uptake of new technologies. Very cheap cost-focused company, which can be certainly be good, but not always. Sometimes the company doesn't want anybody buying anything... even basic office supplies are heavily scrutinized. Recent round of layoffs targeted very talented workers with a high amount of tenure. This was very concerning to me, as I had hoped to make Atos a long-haul company for me. Management has asserted that teams that are working well over 40 hours (due to be short staffed from layoffs and attrition which they won't backfill) of being OVERSTAFFFED. Yes, you read that correctly. People working themselves to death are on an OVERSTAFFED team according to management. So basically a total disconnect from leadership and regular employees. Org chart is not at all flat. So many different layers, it can be hard to get things done. Employee moral is overall very low.