Pros
Working with the smartest, most ambitious engineers and scientists in the United States. Few constraints, particularly concerning money...if you need something, even if it costs 100K (or a million...), you'll get it. Uncle Jeff is on a mission, and if you need something, go get it...in fact, get two in case one breaks. None of the typical oversight or control functions you'd normally expect in a "human-capable" rocket manufacturer, so there are fewer obstacles to moving forward with the design/development process. The engineer is responsible for every aspect of his/her part or function, from design through prototyping, and then selecting an outsource or in-house manufacturing strategy, and finally QAing your parts and determining flight-worthiness. This strategy is not accidental...the whole idea was to throw out big-box aerospace's burdensome infrastructure, where it takes 5 managers weeks to make a simple drawing change. With very few exceptions, the engineer is responsible for providing a flight-worthy part/function/procedure.
Cons
Not much mentoring or hand-holding. You're expected to know your stuff, and to figure out how to make it happen. Tremendous growth in the last couple of years, without having a seasoned management team in place, has resulted in under-qualified people being pushed into levels of responsibility for which they aren't prepared. Confusion about direction and scope are common, and I personally advised a number of young engineers about navigating the confusion. Basically "Figure out what you're really good at, then find a team that needs that talent real bad." Good engineers were occasionally consumed in the confusion, but I believe the senior leaders felt that was the cost of growing the company rapidly.