One of the significant changes seen on Android 4.4 is the new Google Experience Launcher. The launcher is clean and comes integrated with Google Now. You can just say "Ok, Google" while you are on the launcher and it will automatically launch Google Now.
The extracted APK of the launcher and the Google Now from the system image of Android 4.4 works well with the devices with Android 4.2 or above, but not for those with Android 4.1 device. I am among those who really want to experience the Google Experience Launcher but just because I am in 4.1, I can't use it.
I was able to install the new Google Now, new Google Play Services and Google Home app which were extracted from the system image of Android 4.4, but it ended up giving me force closes and didn't worked for me.
I found a Kitkat launcher on Google Play Store today and I am very happy to see it working out of the box. This 3rd party launcher is just like Google's Experience Launcher with almost the same features and functionality. The homescreen and the app drawer are same as in original Android 4.4 launcher.
You also get the Nexus 5 wallpapers packed with the launcher. You can add widgets, apps on the homescreen just like in the Experience launcher. Even though it is the initial version, the launcher is very stable and smooth in performance, but it still lacks some features.
The launcher uses the default icons but you will be able to use icon packs with the launcher soon. You get a persistent Google Now search bar at the top of the homescreen, which you can't remove for now. You can create multiple homescreen pages just by dragging an app from app drawer to a new page. The small rounded indicator above the dock shows you the page you are on.
The launcher also allows you to create beautiful folders. You can group apps to create a folder and you can define a name for your folders. I am not sure about the original Experience launcher, but this launcher uses Roboto condensed font for icon labels on the homescreen and the app drawer, which actually looks good.