Pros
Working at SpaceX has been amazing. I have developed software since a young age, and had my soul drained at my last big-corp job, but working at SpaceX has rejuvenated me. The work is interesting. My manager is technical and intelligent. The mission of the company is inspiring. A lot of my friends told me that the work-life balance would be bad, but even after 5 months, it has been great. I just talk with my peers and set realistic expectations on what is going to be delivered. I have yet to have to work late. The on-call rotation is light too, and every week our team spends time reducing noisy alerts.
Cons
You have to be able to be your own boss, learn to say "no", and take ownership and the stress of your area of expertise. You are responsible for your own work, and everyone has brilliant ideas, but you have to take a deep breath, and prioritize on what is important. Also- working at the office is required.