Pros
Every level can make an impact here. After 11 years, still feels like a start up, but with developing process/structure/policies. Twitter is a global brand name. If you like the spotlight, and getting lots of attention when you say "I work at Twitter," then its a great place for you. The company is competitive in salary, making big adjustments on promoting growth internally, hiring better leaders, hard workers, and people that really care about being a Global "NEWS" source. Great work balance. Amazing perks - Free food all day, booze, cell phone, gym, etc. No formal vacation policy and 5 months paid Mat/Pat leave by far the best in the country. They make it comfortable to work here.
Cons
Still stuck in the stigma of "social media" and wall street measuring success by one poor measuring tool - "Monthly Active Users." Not much else.