It really depends on your team. I didn't feel connected to my team at all, and they didn't seem that interested in me or what I was doing. The test environment broke all the time and people didn't care. I was stuck with an underpowered dev server for the first 2 months which made everything very slow and flaky. Sometimes it took weeks for people to review my code. When planning my project, one teammate kept harping on the fact that it's "an intern project" and "Maybe he doesn't know how to code."
My manager was not a good mentor. One of the first things he told me was how his previous intern's project is no longer used in production at all. He often acted as if things could be done in a "few hours" or "a day" when it would obviously be more work than that. When I was almost done planning my project, he changed his mind and wanted part of it to work completely differently.
That being said, the food and perks and corporate housing are great. They throw a ton of cash at the intern program. It's also cool to listen to Mark at the Q&A every Friday.