Pros
95% of the people are fantastic. Life long friends. Pay and perks are great. The company (not some of the employees) tries to be inclusive. Facebook is a great platform, and the company, regardless of what the press says, is made up of a lot of ethical people that want to do the right thing.
Cons
Oppressive twice a year reviews that have employees turn on each other and management. Bottoms up leadership means there is no leadership. Zero direction, multiple people working on the same project in silos. Innovation hostile even though management talks about innovation all the time. If you are not young Asian, white or Indian you may be uncomfortable. The 5% of toxic employees do a lot of damage because there are so many nice people. My group, strange as it may seem is very conservative with a lot of ex-military. This mind set perhaps works for the military, but not a tech company in a rapidly changing world.