Pros
1. Unique mission - You sometimes take it for granted but you don't ever have to worry that your life's work is meaningless. 2. Great people - Almost everyone around will be as smart or smarter than you which is a great environment for good ideas to develop and personal growth to occur. 3. Interesting problems - Both designing and building rockets are hard. 4. Equity - You get a slice of a company with a great future. 5. Perks - The full coffee bar, frozen yogurt, heavily subsidized meals, generous vacation days, and flexible schedule make a challenging work environment doable.
Cons
It is not uncommon to feel overwhelmed. There is so much work to do, so many problems to be solved, and so many people dependent on the work that everyone else is doing that there is a good deal of pressure to deliver. Parking is a bit of a pain. Life in LA is expensive.