So being one of the few people in this thread that has worked with Jason, I wanted to chime in for a second.
Jason is totally demanding and pushes everyone around him to their limits. Yes. True.
But, underneath all the bulldog, seriously the guy has a heart of gold. Sometimes he doesn't show it, and even he'd admit some level of narcissism, but from personal experience, I can fully say that working with Jason changed my career for the better in every way.
I originally worked with Jason at Weblogs, Inc., and as we were acquired by AOL, worked with him on the relaunch of Netscape. I went through a personal tragedy during the launch of the site, and Jason / the team were instrumental in me coming out of that with my wits about me.
To be clear: Jason is hard to work with. He does joust publicly, which I would attribute to his form of marketing.
I have absolutely no inside knowledge of his actual tactics, but my guess is he takes on someone who he knows people don't like, then points out their flaws over time, figuring eventually he'll come out on top since his side of the story looks so rosy by comparison. Oh, and he does this by being fairly hyperbolic. (Mainstream media, junkets in journalism, Gawker, Pay-to-play angels, SEOs, off the top of my head.)
That all aside, I think working with Jason set me up to have a wide-eyed view of startups. I treasured the experience, and while I think everyone should evaluate their personal limits carefully before embarking on a career with someone who will literally push all of them, I don't think anyone who's worked with him has regret the time they spent with Jason. That doesn't mean all of them want to work with him again... but I heartily encourage anyone who wants to be pushed to work with him. It will be a hugely rewarding experience professionally. It was for me, anyway.