Pros
High hiring bar, get to work with intelligent people, lots of opportunities to learn/grow, great tools, high impact, international exposure, lots of fun!
Cons
Work life balance was tough when the company was smaller - but that is always the case with small companies in high growth mode, at present this issue has been addressed. I have not seen any international company work seamlessly across many different time zones - Twitter provides all the technology to support this though & the flexibility to ensure you work from home or take time off in lieu to balance this out. I have experienced some "micro-managers" during my time here, however with the very open and fearless feedback environment, those people learn to be more trusting, open with their directs.