Exposed me to lots of friendly people who I learned a lot from; both about how campaigning works and how jobs in campaigns work.
What I wish was different
Only thing I'd change would be either a little pay or providing gas/lunch money, but that wasn't a surprise when I applied or anything.
I would advise anyone interning on a political campaign to be sure to put their all into it in order to stand out. If you're not showing the full-time staff that you're there to put your all in, they won't notice you.