Vantaggi
Great core values, eng principles, and org skills help everyone be better employees and build the best products Twitter University makes learning scala, python, and even management a breeze. Extreme transparency from the leadership. You get to work on an incredibly important product with huge impacts on the world. Low performers are actually fired. Great perks - food, barista Impact is rewarded, not politics. Engineering management encourages rigor. Work/life balance is great, I get a ton done and work 10-6.
Svantaggi
As the company grows up, the old hacker culture and the new rigorous engineering cultures are clashing a bit. Gone are the days of shipping lots of hacky MVPs and moving on to the next shiny thing. This is a product that hundreds of millions of people use, so rigor has gone up a lot. This can result in different engineering philosophies and different levels of quality in the same system.