Pros
New company, colleagues are diverse (including age). Everyone, without exception, is competent, and so far, nobody is political. The mission is interesting. I think there are employers in the area that pay more, like Blue Origin and SpaceX, but they prefer only a certain demographic (again, age) and are oppressive to work with, judging from ex-employees. All due respect to them. Here, I feel like we are equally driven, equally forward thinking, but not as visible, and unmanned space has never been sexy, so we're not going to get the attention they do. Fine with me. I'd recommend this company to those who are also driven by moving forward in space without the office politics.
Cons
HR can be a nuisance, but I've never worked anywhere where they aren't. But because this is a small company, it's not a vacuous beurocracy.