I didn't know much about Wil before Table Top (well, aside from him being on Star Trek Next Gen), and I have to say he's impressed me. He comes across a bit like he 'knows' he's a little famous, but not in a jerkish way, almost more a tongue in cheek kind of way. Table Top is a freaking great show, I really think one of the gaming networks should try picking it up for a season and see if it goes over on cable TV.
The two moments that I think won me over best were when he was asked about 'geeks' getting teased while on a panel at a con... phenomenal response, especially to a youngster who will likely take that moment with them through the rest of their life. And the other one was when doing X-Wing on Table Top where he said, a number of times, with great emphasis "Han Solo ALWAYS SHOOTS FIRST!" I had to rewind that a could times just for the heck of it.