Pros
Interns are given real tasks and are part of the team, and they really want you to learn as much as possible.
Very laid-back casual environment, but they still do real work.
The departments know each other. Sometimes this doesn't happen at bigger companies.
It's a respected company and will look good on your resume because they make you do real things.
They like to hire interns. If there had been an opening, I was assured that I would be considered. While I was still there, they hired a past intern as a freelancer so you know they mean it.
Cons
Interns don't get paid. (Although I hear they do now. Of course!)
It's VERY fast-paced and at times there can be a lot of pressure. If you aren't willing to work hard and get the job done, not the place for you.