Pros
As a space nerd and believer in American manufacturing SpaceX is a tremendous place to work. We take raw material and turn it into something shot to orbit. That is a hugely satisfying thing after coming from the typical aerospace giants and a driving force behind my continued interest despite getting beat up by my job. Once you've found a niche the job is rewarding beyond anything I imagined it would be. Pay is average for a non-union aerospace company and the benefits packages are nice. The offer a wide variety of insurance plans that make it affordable even for a big family like mine. The chance at constant overtime is nice. Stock equity is a nice touch but no 401K match is definitely a con.
Cons
Manufacturing jigs, fixtures, assemblies, and even launch mounts from raw material means the job is very labor intensive and often out in the elements. You need a pretty good state of health because this job will send you home everyday feeling exhausted. If work/life balance is a phrase in your vocabulary this job will break you. SpaceX plows ahead demanding between 70 to 80 hours weekly from you. Of course for those money-hungry overtime hounds it's fantastic because you will more than double your yearly base salary. SpaceX is very much sink or swim from the very beginning. You must be willing to quickly adapt to new situations and demands that are above and beyond what a normal aerospace company would expect. The day I started my supervisor said "SpaceX only wants badasses", and that has been proven by a number of people who didn't fit the bill being sent home. You must be very even tempered and able to work closely with the people around you.