I really enjoyed my experience. I mainly worked on stories for their blog on blahgirls.com, which no longer exists, but I also got to contribute production ideas, do some script coverage and even got to work on set. Katalyst also films a 'behind the scenes' series that airs on Facebook called "KatalystHQ" that I got to be involved in once or twice. The employees were younger, mostly laid back and generally had great senses of humor. I learned a lot just by listening to the conversations around me and asking questions.Various celebrities would always be in and out of the offices.
I have to say that my positive experience was mainly due to my great boss, who no longer works there. She would always respond with positive feedback whenever I contributed work and made me feel super comfortable. Although she was in the digital media dept, she involved me in other areas she knew I was especially interested in (like working on set, for instance).
With that said, I believe that their internship program has become a bit more structured and for credit.