I've enjoyed the PAX games (even if they're completely ridiculous. I'd hate to play in a game that was quite so off-the-wall, but they make for good entertainment as an observer.) Plus it's cool seeing people like Morgan Webb and Patrick Rothfuss playing the game. I never cared for the Podcasts with those players, though. I need the visuals.
I just watched the first 90 minutes of Critical Role (Matt Mercer and Co) last night and found it incredibly entertaining. You can tell at least some, if not all of them, have some background in Improv, and their ability to play off of one another and Matt Mercer (the DM) is really quick on his feet in reacting to his players. Plus, as one would expect from professional voice actors, each character has a very distinct voice and personality separate from the players, and they're all very obviously having a blast.
In a lot of ways it reminded me of some really good sessions I've participated in, where everyone just gets into the right rhythm of give and take, and the results are practically magical. It doesn't happen often, but it's fantastic when it does. I'm curious to see if that continues in later sessions, or they just happened to catch one of those high-point sessions in their first episode.