Pros
I previously worked in finance, Mars is definitely a completely different vibe. People have very strong respect for each other and work-life balance, 9-5 style here. Very flat hierarchy, I can talk to senior directors who are 3/4 layers below the CEO any time I want. Dog-friendly, wfh-friendly, flexible working. Tons of great events for graduates, like proper Halloween gatherings, Christmas events, etc. (tho I suppose it's not specific to here, but they do put in strong effort)
Cons
Some offices are quite far (e.g., Slough, Waltham, Castle Cary), but these offices tend to have very strong wfh (once a week, sometimes even once a month if its VERY far). Diversity could be better, though there's very strong active effort from management to recruit not just white people lol Top 80 percentile salary, so it's really decent, but don't expect IBD or Consulting-like compensations (obviously lol)