What I liked
I learned a lot - not just about programming and software development (design, code reviews, unit testing, etc etc) but also soft skills about how to communicate with coworkers, present my project, and build relationships. I also gained a ton of insight into their internal relations and how they organize the company.
I had two supervisors to seek advice from as well as a mentor from an unrelated team. Most importantly they offered a lot of intern / company events and had amazing food all the time.