Pros
Really nice people work at Cargill, for the most part, however it is a very, very large company, so it depends on which division (platform) you work in, and of course your direct manager can make or break the job. As a huge, global company, there is a good range of career paths. You take control over your career path - managers encourage meeting people and developing your network so that your career can blossom. Careers are enabled and supported by senior management and HR if you are committed to the company. As a trader, it's a great training ground.
Cons
Certain divisions can be less appealing than others. Cargill is a private company which is good in some ways but they remain afraid to communicate, and in some divisions this extends down to employees which can hinder motivation. Marketing is very underdeveloped as a discipline. Cargill is notoriously cheap - only very senior-level employees are given permission to fly business class and the hotels people are expected to stay in upon arrival are often sub-optimal. Because of the vastness of the company it is difficult to understand.