First off, congratulations! Chiming in as someone that interned at fb summer of 2016 (menlo park) and worked there from 2017 to 2020 (seattle)
Obviously your mileage will vary. The company was in a very different state in 2016 than it is now, but I'll list out the pros and cons I had going through the internship:
Pros
- Pay is good
- Free food is nice (if you're in person)
- Most if not all the people I worked w were great
- Nice to have some brand name on your resume
- This number may have changed but the signing bonus they gave to return interns starting fulltime was $75k so if you get an offer, this can put a real dent into your student loans if you have any
- It's maybe valuable to experience what the vibe is at a big tech company at least once (this was my reasoning for accepting the offer since prior to this I had only interned at smaller start-ups)
Cons
- The intern classes were v big and as a result, I didn't feel the same intern camaraderie I felt at internships elsewhere (also did not help that I was living in SF and commuting to Menlo Park, but also the intern events had like hundreds of people and always felt impersonal to me)
- I didn't feel like I was well matched to the intern project I ended up working on. While it was a part of the stack I wanted to work on, I was p disinterested in the actual substance of the work. Unfortunately interns don't get too much say on what they work on
- Similarly, who your manager ends up being and what the culture of the team you're working with will really impact your experience. I found I couldn't relate to a lot of the folks on my team as an intern (they were mostly parents that lived in the south bay which nothing against it but idk, me at 21 found this p jarring)
- A lot of Meta's tooling is internally built/maintained. While you're gonna be able to take what you learn and apply it to other places, they'll likely require some translation. A simple example is Meta uses mercurial whereas most places use git. (FWIW I actually prefer mercurial now having worked there full-time for 3+ years)
- Everything else having to do w Meta in the news etc.
I'd say if you do end up accepting, try to renegotiate it to a smaller engineering office, since the vibe at those places will end up being a lot different from the main campus (and IMO more "homey"). Personally, I found my internship experience pretty meh, but hey I accepted a full-time offer there (mostly to pay off student loans lmao) - but ended up staying way longer bc I ended up working on a team and product space I really vibed with.