One issue is that the Google Now panel, located to the left of main home screen, does not work with non-Nexus or Pixel devices. (mobilesyrup.com)
Apple newsstand is apart of the new iOS 5 update and will be on your devices main home screen. (goodereader.com)
And while I like the idea of the predictive app collections and simple main home screen, I just don't see enough value in those items to also deal with less - than - stellar predictive information in the Smart Screen. (androidcentral.com)