Pros
Flexible work schedule, responsibility in complex and long-term projects (worked as a junior engineer), was invited to attend to attend high-level meetings with clients and felt welcomed by executive management, ability to explore career interests outside of direct assignments, strong Junior and Mid-level Professional (JuMP) networking opportunities, strong intern support program through weekly skype trainings, friendly and hard-working people--no slackers!
Cons
Many full-time employees work remotely--good for work life balance but bad for forming relationships since in-person interaction is inconsistent. CH2M was recently acquired by Jacobs Eng. so there is a lot of uncertainty with job security, management changes, and shifts in company culture.