Pros
I've been at Facebook for more than six years. The culture is very introspective and dedicated to self-improvement; if it were the same company it had been in 2009, I wouldn't still be there. Everytime I think I might leave, a new awesome project comes up that keeps me around. Seeing Mark Zuckerberg mature into the great leader he is has been magical, and I have a lot of trust in Sheryl and Mark and Mike Schroepfer to make good decisions.
In many ways, engineers are more productive now than they were in 2009, despite the fact that we work at a big company now. We have more tools, resources, and knowledgeable people at our disposal, which compensates to some degree for the increased bureaucracy you see in some parts of the company. We also launch to hundreds-of-millions-to-billions of users, depending on the product, making our contributions very high-value. Product launches continue to be driven by bottom-up ideas as much as top-down directives. That doesn't mean that you personally are going to have an idea which shakes the world, but it does mean that you have a better shot than other companies.
Especially if you're an infrastructure engineer, the culture is very bottom-up. You still have great latitude to come up with execute your own ideas. The flipside of this coin is that if you're not good at deciding what to work on, you'll need to learn that skill within a year or so; management isn't going to spoonfeed you tasks to the extent they do at other large companies.
When joining Facebook as an engineer, you will still have many many choices of which team to join, and you'll make that decision after a few weeks of "bootcamp" which means you'll have an informed choice. It also means that the quality of engineers is high throughout the company because every person comes through the same interviewing process.
One of my favorite aspects of Facebook culture is focusing on impact rather than hard work. Another is a recognition that you can advance your career without going into management, and that there are many different kinds of talent. There are several different "archetypes" of senior individual contributors that are recognized and encouraged to flourish.
Cons
Facebook has become more careful in certain core areas like Newsfeed, Timeline, Ads, and Platform. There are many stakeholders on these products and thus you've got to get a lot more things buttoned up before you can launch a product change in these core areas. We still do experiments but not quite as freely as before. Just understand that the more impact your product has, the tougher it will be to make changes, and place yourself in the company according to your preferences.
