Pros
Decent benefits, though not as good as they believe it to be. Good 401(k), good medical. Vacation is sub par, with sick days mixed in, and max's out much lower than other industry companies. Excellent diversity in actions and relationships. I've never seen a negative diversity issue. People genuinely want to help the world and some of the finest minds are inside MITRE. If you have a thick skin and can put up with a lot of people with inflated egos, you'll be fine.
Cons
The company has incestuous, group-think, leadership. Getting ahead in MITRE is not based on performance, as they tout. It is truly how well you promote the fact that you promote MITRE as being a great company. People share any mention of MITRE in the press as a great celebration. This group think causes many to be blind to faults inside MITRE. #1: There is so much suckling on the government dime that there is a genuine FEAR of offending a government sponsor. Even if there are serious issues in what the sponsor says or believe, you cannot address it head on. You are only allowed to hint or hope that the sponsor will change. This is particularly true of public sector FFRDC work. #2: If you are hired from the government, you will enter MITRE at a pay level above the equivalent hire from industry, This is a bias that I wish qualified for an EEO complaint, because it is rampant. It also fuels the group-think, government suckling mind-set. #3: There is huge amount of waste inside MITRE making it hard for it to be competitive. Advice for eliminating waste is ignored by leadership, because when they think about it, they realize that the company is top heavy and to eliminate waste will eliminate the need for as many leaders. #4: The top leaders are elitist that have vocalized on webcasts a disdain for the rank and file asking legitimate, but hard, questions. Those with legitimate scientific concerns on MITRE's COVID-19 stance were openly ridiculed, even when quoting peer reviewed studies.