Pros
Mars recruits high caliber people and provides 'BIG' jobs at all levels. Analyst positions at Mars can have the same scope and level of responsibility as Director levels at other companies. They like you to change roles every 2-3 years so you gain diverse experience across the organization. Mars pays above average, but you have to factor in the real value of the work, in my example the pay may be high for an Analyst but low for a Director.
Kontras
The downside at Mars is that you need to manage your own career development. You must assess for any internal opportunities (lateral or promotional). Your direct manager does not have the ability to give you a promotion or to impact your salary increases. Which means for the high performing, self-directed associates they tend to hire, managers have little value.