The Hasbro panel didn't really cover any new ground, choosing to discuss War for Cybertron, the upcoming DLC and talking about the next wave of Transformers toys with the Hunt for Decepticons, Power Core Combiners and Generations lines whose information has already been released over the last several months. A summary can be found here. The slideshow of toy images from the panel can be found here. A gallery of Transformers toys on display at the con can be found here and here.
The Transformers: Prime panels were probably the more interesting of the two with the participation of Roberto Orci, Alex Kurtzman and Peter Cullen. Below are two videos, one shows off a brief video of Peter Cullen and Frank Welker at work and the second video is the test scene that gives you an idea of the CGI being developed for the series. The main reveals is the series is based on a 350 page lore book that Hasbro has. It’s not entirely clear but I got the impression from reading various summaries that the series is set in the War for Cybertron continuity and events are inspired by the movies but not exactly taking place during or after the movies. The basic idea is Transformers are in disguise on Earth more or less in the present day, ready in case the Decepticons attack. There is a human cast, but none related to the movies. The summary of the panel and a gallery of images that show off the Transformers and human cast can be found here.
If test scene doesn't appear, click here to view.