Pros
I am currently a summer intern at Cisco, and in terms of summer internships, I can really say that they have given me real hands on experience with real responsibility. I came in barely knowing what a network/router was, and I feel that I have been able to learn a lot from my co-workers who are always more than willing to help me whenever I have a problem. My pay is very good compared to what most of my friends are making, and if I were to work overtime, they would give me time and a half. It also looks good on a resume
Cons
Looking around, it seems that people (especially with pending deadlines) put in A LOT of overtime and complain that they aren't properly compensated for it. It's also tough because there are some crazy people who will work 80 hours a week and then that will put the pressure on everyone else to step it up.