Pros
I can only speak for the contracting side of Battelle. It's a good, stable job for a technician who wants to put in their 8.5 hours a day and go home. Management had little to no idea what their workers did for the contract and very limited contact with that staff. Decisions based on work performance were made entirely on the client's review, which could be good or bad depending on your on-site supervisor.
Cons
Workers who achieve more than required or take on extra responsibility are not compensated in any way and there is no room for professional growth. You will never get a promotion/raise because you can never exceed your base job description of "pleasing the client." Communication between the client and Battelle management is poor, meaning that each side blames the other, nothing is resolved, and the employee suffers. This is a corporate machine that exemplifies the worst of big companies. If you want to be respected as a human being and an adult, I suggest you look elsewhere.