Pros: Great colleagues, lots of impactful work.

Cons: Can be stressful at times.

Pros: Good salary, friendly coworkers, and a lot of benefits like free food and free laundry.

Cons: Work-life balance is so bad. Average 50 hours+ per week.

Pros: The work: Facebook is growing fast, which means there's a lot of opportunity for career growth if you're motivated. My co-workers range from good to stupendously great engineers, and I've seen no sign yet of a decrease in quality in the new hires. The product: It's an incredibly rare opportunity to build products that are used by 1/6th of the world's population. I can visit the most far-flung corners of the world, walk into a cafe, and see people using the thing I've built to connect to their friends and loved ones.

Cons: It can be stressful at times, and maintaining work-life balance is tricky. I think this is mostly an internally driven thing rather than imposed by the company, but it is what it is.