According to AndroidGuys, content providers include "MTV, NBC, Paramount, Universal Studios, and Warner as partners, with more content providers to be announced." Androinica also includes Nikelodeon and Comedy Central into that list.
Unfortunately, only the US variants of the Galaxy series will be able to access Media Hub. Androinica theorizes that the content provider partnerships may "have prevented them from being included on international versions. Multiple Samsung reps I asked were unable to answer if international versions would be available but repeated the similar line that they are focused on launching in the United States."
Android Central reports that "television shows will be available next-day" to watch, and that users won't have to wait for a download to finish in order to start watching.
Check out this hands-on of Samsung's Media Hub below thanks to Androinica:
Engadget comments that the Media Hub "is new, is sleek and convenient, and the Iron Man preview we watched looked great on the screen."
Image from Engadget