Pros
For me, the main reason to work at SpaceX is an unparalleled sense of accomplishment from seeing tangible results of my work. A close second reason is the smart and motivated people I work with every day. If you have a passion for space exploration or global communications, there should be no need to explain why SpaceX is the place to be today. If you do not, then, well... it is best to work on something that you have a passion for. One more thing worth mentioning is that for the company this size there are practically no politics to speak of.
Cons
Cons are a matter of perception. Personally I have nothing to write here. If you were a sports car enthusiast speeding down the raceway would you complain that the seats are tight or that suspension is stiff?
