Pros
What you work on improves the world. Because you're tasked with doing something that hasn't been done before, you're constantly bumping into problems that you're the first human or group of humans to encounter. You get to work with the world's most talented people. Despite (or perhaps because of) the extremely high expectations everyone operates under, conflict is almost entirely related to technical issues. Very little interpersonal drama. People are understanding if you hit your limit because they can relate, and there's a strong culture of comradery. To a person, everyone is competent and dependable. You'll essentially never find yourself avoiding or going around a colleague because you anticipate they'll be unresponsive. You're constantly learning new technical skills, but you also learn a lot about yourself at the same time. Very little bureaucratic red tape, if you've got an area you can contribute, management will not get in your way of pursuing it. Advancement is quick if you're talented and driven. The company is managing scaling very well, and I'm a firm believer that it's most impressive accomplishments have yet to occur. My contributions here are one of the things I'm most proud of in my life, which is a feeling you won't get from most jobs.
Cons
Very demanding and intense. A place where you need to be very deliberate about what you want out of your work/life balance. Unless you're superhuman, burnout is inevitable. You need to be able to consciously monitor your own burnout. The constant threat of an embarrassing Elon tweet/story (I never saw any of these attitudes trickle down to my department, and I would not have tolerated them on my team. I firmly believe my experience would hold across the organization as a whole). Remote and work from home policies are unnecessarily strict. Minor thing, but the company can be weirdly cheap about little things sometimes.