The demo is laggy on my iPhone 4. The "fixed" header and footer don't stay fixed when scrolling; they only jump back in to position after the scroll ends, feels like a pre-iOS 5 Javascript hack. None of the navigation seems to work.<p>Maybe the experience really is better in an IE browser (never thought I'd say those words), but I highly doubt it. I haven't known any browser - Windows Phone or Android - to handle HTML/CSS/JS better than iOS, so I'd be really surprised. I'm going to be attending a Windows Phone demo event thing this week, will test the demo on a Lumia 900 there and see how it runs.<p>I really like Metro, and want Windows Phone to succeed (more competition is always a good thing), but this feels like a miss to me. Cordova/PhoneGap support is a big deal, and a great pursuit on their part, but as far as I'm concerned jQuery Mobile should be taken out back behind the barn. It looks cheap and performs horribly, and it gives mobile sites and apps a bad reputation.