Pluspunten
Pay as a researcher is excellent. That is the only thing that keeps people here. You know where this is going... Good flexible hours, benefits etc., with some stigma attached. Highly recommended for those who want a job where they can 'coast' with high pay and little likelihood of being fired. Low-stress job after a few years. Good opportunities for shifting to management role if desired. Plenty of rotational/travel opportunities. Lots of career paths to choose from. Plenty of smart people to work with and around. Plenty of interesting projects to work on.
Minpunten
The management at Clinton, NJ has essentially commandeered the ranking system as a method of lining their own pockets and rewarding their political allies. Your 'rank' at the R&D headquarters is mostly just a measure of your political success. I had to see it for many years to finally believe it. The quality of the engineering work (and innovation) you do is irrelevant to your rank, as long as it meets basic requirements. As a researcher with a PhD, this may cause depression after some number of years, but you will get over it! Exxon is a top-down company with strong managerial control. The top-down approach to research prioritization produces awkward results. Be prepared to work on programs/projects which appear totally pointless to you and your colleagues. Micromanagement is very common, as managers were once engineers themselves. No method of underlings to review supervisor performance. It is a one-way street.