I worked at Facebook in Fall 2016 on Infrastructure. Work-wise, Facebook's internship program is very well structured; they really focus on providing mentorship and tools that allow developers to come in and ramp up quickly. I had a great relationship with my team and a lot of respect for both my team manager and internship manager; they were all very keen to make sure I was enjoying my time there. Dev experience is very polished, I was never blocked on infrastructure not being available for me to work on my project.
Benefits are probably top-tier in comparison to other tech-internships, you also really bond with other interns outside of work. This is a great choice!