Not to take away from the performance improvements and improved integration that this will bring to Firefox for Mobile, but this new UI means that almost all mobile add-ons will have to be rewritten or significantly updated. Granted, there are less than 200 add-ons that support Mobile, but I'm responsible for 5% of those, and the time it will take to update them to support the native UI might not be worth the effort.<p>(A similar situation occurred between Mobile 1.0 and 2.0, when browser UI and Web content were separated into their own processes, requiring any add-on that dealt with content to be updated. I still haven't finished all of those changes.)