Pros
For the right person, there are lots of opportunities to grow your career. Amazing, dedicated, smart coworkers and a highly collaborative work environment. For the most part, teams and individuals are oriented towards working together to accomplish ambitious goals on aggressive timelines. Management is pretty open and accepts that imperfection comes along for the ride in a company trying to move as quickly as Guardant is. If you are highly technical, oriented towards getting stuff done, enjoy working cross-functionally, and can manage some amount of chaos, Guardant can be a great place to work.
Cons
Relentless pace- little time to rest or celebrate between milestones or projects. The fast pace comes with downsides in terms of work/life balance- the company will take as much as you have to give, and it will be up to you to define boundaries (the good news is that those are generally respected). Still some organizational immaturity in terms of structure and process. I can understand how more junior colleagues might feel that development opportunities are limited, given the lack of formal development programs and how busy most senior staff are. Guardant seems unlikely to give up its ambition in any significant way, which means that the fast pace nature of the company will likely persist for years to come. There is movement towards improving aspects of the culture (management training, coaching for senior leaders, etc). However, if you are someone who needs well-defined structure, clear direction, and company-guided work-life division, Guardant may not be a great match.