Vantaggi
When I talk about SpaceX, I don't say that it's a peak career experience - I say that it's a peak LIFETIME experience. If SpaceX is for you, it will absolutely positively blow your mind. You will never be the same again, and I mean that in the best way possible. There is a high degree of self-selection in the recruiting process at SpaceX. If you learn about Elon Musk and SpaceX and you are inspired to learn more, inspired to read and absorb everything you can about them, and are willing to do whatever it takes to get hired here, and then do whatever it takes to be successful once you ARE here, then SpaceX is definitely for you. If the preceding verbiage does not describe you, then it's probably not for you, and it's all good either way.
Svantaggi
If SpaceX is your cup of tea, the things about SpaceX that some will describe as 'Cons' or 'Downsides' won't occur for you as such in the least. They are just part of life at the X. The reality of working at SpaceX is that it's an intense place to work. It will call you to bring your A game and find out what you're made of. Sometimes a sprint, sometimes an endurance test, sometimes both, it is a mission more than it is a job. If you're just looking for a job, don't even bother applying at SpaceX. There are many easier ways to make a buck out there. But to my knowledge, there is no company more exciting, inspiring, and awesome in the entire solar system.