Pros
Facebook has a lot of money to throw around, so you get great benefits and perks. Office spaces are nice, the benefits are really good, plus they continuously update their 'Life@' perks which can be handy and convenient.
Cons
The worst part about Facebook is the culture. With the excuse that you should 'focus on impact', people will fight for 'sexy' projects and things that will obtain them a good performance review. Since middle and upper management often do not have a clue about what their own teams actually do, whatever you can make sound important (e.g. with fake metrics or tales of potential impact), you are onto a winner. Unfortunately, the same managers do not enforce a culture of fairness or trust; instead, it is a culture of rewarding back-stabbers and people who 'get the work done' but who, at the same time, treat their colleagues poorly. By that, I mean stealing projects or not giving credit to those who get the work done, for example. It is an awful environment to work in. Some teams are worse than others as well: You could end up reporting into a bad apple who steals projects from you. It happens, and it happens often. Good people managers are never rewarded, as people management is not something Facebook recognises as important. Yes, in the orientation they will give you a big speech about it but when was the last time good people managers got promotions? Managers should focus on people, and ICs should focus on things. Unfortunately, bad managers who are good at IC work get rewarded often to the detriment of their teams, who have to suffer under people who should have never become people managers. The so-called Pulse survey is a joke, as no importance is given to low-scoring managers. If 10 people in a team say they would not work with their manager again, something must be wrong, don't you think? To any potential employees: Do not get fooled by the appearances. Facebook makes people feel trapped because they make you think this is the 'best' company and that you should be grateful you are part of Mark Zuckerberg's dream of making the world more 'open and connected'. It's a fallacy. Do not fall for it.