Pros
Good pay, great benefits, some genius people work there. EMIT is a nightmare, but in other departments I had friends have quite positive experiences.
Cons
I would never recommend any of my computer science minded friends to work here. The work received was fun and challenging, but the management structure at XOM is atrocious. I definitely left work unhappy more than I did happy, and my friends in the company were basically the only reason I made it as long as I did. Management is largely untechnical... yet hold a lot of your technical career in their hands. Management is also full of extremely unfriendly and unmotivated individuals, many just care about climbing the corporate ladder. The job roles you are given probably won't line up with your skill set or your desired skill set.