Pros
This company might be a great fit if you are early in your career, as you will be expected to only code, and that is incredibly valuable to Junior engineers looking to ramp up their skills and recognition of common coding patterns. The company undoubtedly has product-market fit which means that the problems are now problems of scaling a product that has been built in haste (and to the early founders' and employees' credit, very impressive). A lot of technical debt exists and this may be very exciting to new joiners, or also very exhausting if the solution being implemented is overwrought or short of industry best-practices.
Cons
Resources (i.e., FTEs) are treated as contractors who happen to work together, rather than teams who are collectively team building to work on something together. Little to no active career development is given and is completely self-directed as management does not have the incentives nor is able to give the necessary time and effort to actively invest in people's career development. Feedback is one-directional. It is expected to go from a higher-ranking/influenced individual to the employee, but the expectation of basic emotional self-regulation is expected to only go from employee to the individual with more power in the company. This means oftentimes that people managers do not hold themselves to the expectation of perhaps not raising their voice, professionalism, or relying on a culture of attacking other's competence when stress is high or resources are thin. The above creates a top-down dynamic in which the highest managers are often incredibly controlling. This additionally shows through with their proliferation of "gentleman's agreements" that rely on verbal promises about compensation, equity vesting, or role expectations that differ from written contracts. This is unlikely to scale especially when differing opinions or upward feedback is not heard, considered, nor accepted, and often seen as threatening. While management challenges exist at many companies, the combination of these issues here is particularly pronounced.