Pros
The pay and benefits always seemed high. Not that I'm personally complaining, but in the company meetings they told us a constant concern from sponsors was cost of doing business with MITRE. Under the previous CEO many corporate social posts were focused on woke cultural/political causes. I often found myself asking how does this have anything to do with getting work done well? With Mark Peters and the tightening federal budget thankfully most of those have subsided.
Cons
I worked at a site, not in one of the main offices and because we're matrixed I often felt alone at the company like the things I did didn't overlap with people I saw day to day and made it harder to make coworking friends. I felt alone and isolated. Even when I got RIF'd (no hard feelings, I understand) my Group Lead said he was the last person to know. The only thing that kept me there was the pay was nice. They are very focused in tech yet it's actually hard to find consistent development contracts that will last. One major issue with the nature of MITRE and product maturity is that MITRE is primarily a research company: build the tool on a tight timeline to perform research for a sponsor and deliver the results. Yet it seems too many projects get shelved because it's very difficult to advertise them widely enough throughout their relevant user-space, get users on board, and bring them to maturity as a full product rather than it being stuck as a smaller tool.