Pros
Good pay, team lunches, and supportive management. Great location if you want to avoid driving into DC.
Cons
Their speciality is in government contracting, so you are what you are. In other words, when the contract ends, so do you. This is the norm in the DMV when it comes to government contracting, so don't expect any internal promotions because it evolves around that particular customer contract.
There aren't enough contracts to transfer over, so when its done, have your resume ready. But that goes for most small tech companies in the federal arena.