Pros
You get recognized for good work. Benefits are solid. The people are generally nice and managers are helpful from what I saw. You instantly get a lot of respect from people when you say you work at NASA, even if you're not really a rocket scientist. Dress code was extremely casual, you could wear jeans every day if you wanted to. You get some pretty cool perks related to the space program including meeting astronauts and such. The pension plan offered to me seemed fair. Flexible scheduling, most people in my office worked 9 days every 2 weeks. Hours weren't too rigid. Work was easy.
Cons
My work was mostly on payroll and other intranet systems, which is going to be boring wherever you are. You have to pay for your own coffee. Location was in the middle of nowhere and the onsite cafeteria sucked. The pay was very low compared to other offers I had received and since left for. A lot of time is wasted because many of the systems you have to interface with are so old. The offices are old and dreary. The people are old and impossible to relate to as a recent college graduate. I felt many other employees were unqualified for their jobs.