I'm working on a plugin at the moment so that we can pass certification. There's a number of certification requirements that aren't covered by a simple export.
The main issue I've found is that you can only play one sound at once, including music. That's a limitation of IE10 mobile, which my plugin should hopefully overcome. There's also no accelerometer.
I've found performance to be fantastic. There's some weird issues to do with loading local images slowing down the game, but I'm working with Microsoft to try and iron those out. When using remote images or changing the outputted images to Base64 I'm getting 45fps for Mortar Melon, with no optimisation from the desktop version.