I worked for a startup where DARPA had given a fairly generous grant when I started my career (they made a medical training device that the military was interested in). I was jr, so I wasn't privy to the financial details of things, but overall it was very "waterfall-y" and a lot of form filling and box checking. WLB was overall pretty fair, but the key thing is that processes really hamstrung everyone (think MISRA style of coding standards) and morale was rather low. Pay wasn't great either so I left.
I just wonder now that I am more senior and have more financial responsibilities, is defense a financially safe space in case more tech keeps RIFing, even if overall comp levels are low.