I wasn't at first either but actually playing through and staying to listen to him talk, he grew on me. Some things I don't like, as per his actions and some of his prejudices but then, who doesn't have flaws? The guy is passionate about he believes in.
Thats very true. Ulfric is a decent man, despite his flaws. But I'm way to inlove with Whiterun and too loyal to Jarl Balgruff to side with Ulfric. If he didn't want to replace Balgruff with someone else, then I would have joined his side. : )