This livestream definitely has more of an "formal event" feel while Obsidian's PE stream was more of an office party. This one gets more relevant info from the lead developers, while Obsidian's was more goofy/fun.
Obsidian's stream was a plastered Avellone drawing toons, the chat creeping on one of the women there, and JE Sawyer sitting stone-faced through the proceedings looking like he wanted to be anywhere else. It was fairly amazing.