Nokia has released an interesting Android home screen replacement earlier this year called Z Launcher, at that time it is only available as an APK download. Now the Z Launcher is available officially from Google Play that means any one can try the launcher. The Z Launcher is a home screen replacement app, it has an interesting feature called Scribble which allows users to scribble letters on the screen to pull up relevant apps, contacts and more on the screen.
The Z Launcher is not a typical home screen replacement app, it will look for your usage, the apps you open through out the day and based on your usage it will suggest apps, it adopts to your usage. There is not much changed from the time it was first released but its performance has been improved, it is much faster now according to official Zlauncher blog, it also runs on rooted devices now.
The Z Launcher is still in Beta that means there might be some bugs which you might encounter. Nokia has unveiled an Android tablet N1 yesterday, Z launcher is running on top of Android 5.0 Lollipop on N1, the N1 is expected in the early 2015.