Pros
Active cultural push to improve the engineering culture. It's not too often that companies will dedicate time and resources to ensuring things are actually done right instead of just constantly trying to produce features. Ironically honing our technical approach and engineering standards has allowed us to produce said features at improved qualitative and quantitative rates. If you're a curious minded engineer, want to belong to a team that thinks and works together, and want to continuously work for an organization that is willing to allow you to invest in yourself -- then give Stay a shot.
Cons
Like most, if not all, startups the work processes can be a bit rough around the edges. Communication is always something that can be improved: whether it's communication about roadmaps, or between engineering teams. But, the silver lining is that leadership is cognizant about this and willing to improve.