I get that I'm probably not the target market for OpenID since I'm already more tech-friendly than the average user, but I've never thought it was super complicated or "jarring," to use the definition in the article. I set up the URL on my web server years ago (thus securing me as more technical, I know), but it's been great. I can change providers in the background, and I only need to remember one URL. No more usernames or anything. Sure, it could be easier and more widely adopted (chicken and egg), but I have thought it was relatively pleasant for a while.