Here's some feedback from my Icon so far:
Plex; intermittent flashes watching a video, any video like very 1-2 seconds you can see a frame flashed from the video and it appears to be upside-down.
Outlook Mail; connecting to Gmail and trying to go into your drafts folder to bring up a draft email causes Outlook Mail to crash.
Microsoft Podcast App; crashes when attempting to download an episode from a podcast, any podcast.
Camera; I don't know what they did here, but low-light photographs are spectacular! A real improvement over the previous iterations of the camera app on Win8.
Hey Cortana; Voice recognition is not available on your device...could be some setting I need to find to enable this, but just opening Cortana and using voice to search works fine.