Pros
Team - very impressive group of coworkers with lots of different backgrounds who all care about much more than their tech company job. Mission - we have a compelling reason to come in to work every day, and lots of folks outside the company are rooting for us. Advancement - the company is well equipped to help employees grow in their careers, especially in engineering. Balance - very accommodating and low-stress environment.
Cons
Medium has a lot to prove with its current business model, and the future is up in the air. There's been turnover and layoffs in the past year as the company strategy has shifted, but the dust has mostly settled from that by now. For a five-year-old product, there are a lot of legacy features that we need to build around.