Pros
Laid back culture with lots of respect for employees' personal lives. Despite being so large, it's a flat organization and very informal. You can schedule a coffee with pretty much anyone in the company. You can wear regular clothes into the office, and there is a very flexible attitude towards ad-hoc working from home. Because of the multiple business units under the Cargill umbrella, you could spend your entire career within Cargill and never get bored (and many, many people have... 20+ years with the company is not uncommon around here). It is easy to hop from one job to another once you're in because you get priority over external candidates. Employee-initiative is encouraged & supported by leaders: if you have an idea & find support from others, it will probably happen.
Cons
Cargill was established over 150 years ago and is humungous, spanning the globe. Imagine the incredible complexity of taking a company that size, variety, and age, and trying to transform it into a modern top company, where everything is standardized, optimized, lean, data driven, etc.. Cargill grew up during a different era. It's like a behemoth dinosaur trying to learn how to use a cell phone. So, there have been massive changes in recent times, with entire parts of the company being axed at once and many people being let go. Cargill will continue to buckle and shift for many years. It is jarring to see friends or worse, yourself, suddenly let go.