Vantaggi
Colleagues are engaged. Mars brands are iconic. If you're the kind of person who can ignore a toxic work environment and has the skills to do your job, it can be a good place to work since there isn't much pressure to deliver and you can get away with about 40 - 60% actual working time and still be one of the most productive members of staff.
Svantaggi
Too many managers have been promoted based on who they know but have no functional or leadership skills to do the job. You have to spend too much time "networking" if you want to keep your job and you have to know and flatter "the right people" to get a promotion. On the surface it all looks great, but when you get to know people, most will tell you they are unhappy but don't trust themselves to say anything because they know it will cost them chances of promotion - or even their job, so they post over-the-top positive comments on company Yammer and complain at the coffee machine. You have to make a choice if you want to stay in the company.