Pros
A great chance to do just about everything one of the show's producers do. Just the right balance of structure and responsibility versus freedom to explore your own ideas for radio segments. Very highly recommended experience!
Cons
Not really a con for me, but this is definitely the type of internship that you pretty much get what you put into it. The produced piece I made at the end of my internship was a lot of work on what would have otherwise been my own time - a lot of re-edits and late nights - but totally worth it when it was broadcast on air. Also, there wasn't a ton interaction with the show's hosts but for me, that was fine; I was most interested in the work done by the producers.