Pros
Your coworkers are, on balance, very enthusiastic about the work. Most are space enthusiasts which seems to keep the moral levels up even if the work becomes monotonous (which isn't often) or the hours are long (which can be often). The total compensation is above average and there are a wide variety of specialties, from a technical career perspective, to choose from if you are interested in moving broadening or changing your career path. If you like variety in your work, this is a place to consider. Working with space systems means you work in an unpredictable environment where the ability to think on your feet is a must.
Cons
Many departments are understaffed. There is little time for training and knowledge capture. These may not seem like negatives to some. However, it's a field that requires constant learning and growth. The environment we work in doesn't foster that. As an engineer in the first 4-6 years of your career, it's particularly difficult. You are left to your own devices to gain knowledge and experience. It slows the skill acquisition process. On the other hand, if you are self motivated and have the ability to learn on your own, your efforts will be recognized and you'll advance. The bottom line is that you will have to trade off general engineering growth to focus on the needs of the work at hand if you want to get ahead.