There is a lot of chatter currently happening around the performance of HTML5 mobile apps against their native counterparts. Sencha Touch guys have produced a great video showing off HTML5 performance potentials that I would like to recommend to anyone who has not seen it already. Additionally there is a great video from the lead LinkedIn engineer explaining their choice of technology on their mobile app. There are some interesting workarounds in the wild that can help to improve your HTML5 based mobile app performance like leveraging your device GPU with CSS, that you can read more about in this post here. HTML5 is great at solving the mobile device fragmentation issue, but there is still some way to go to fill in the gaps in the range of HTML5 app features supported by the different mobile browsers.