Pros
I came to SpaceX from another US based aerospace company, and was immediately surprised at the quick pace of design and manufacturing. Management is constantly looking for performance and reliability improvements, and new concepts are implemented within weeks or months. That can be nerve-wracking, but it leads to a very dynamic and exciting company culture. Management is very approachable, and they do a good job of rewarding employees for good performance. There are spot bonuses that range from $500 to $10,000+, and plenty of room for career advancement. Direct salary might be less than a traditional aerospace company, but the internal stock grants more than make up the difference. Buybacks throughout the year make it easy to liquidate that form of compensation.
Cons
Work/life balance is a con you will hear from a lot of people, but many employees find it to be quite manageable. It is all about time management, and you need to be as efficient as possible at work. Expect to work more than at a traditional aerospace company, but it is reasonable to have most weekends and evenings free.