What makes Nova Launcher Prime such a highly rated launcher?

Nova Launcher

One Word Answer: Customization..

Nova launcher is one of the best launcher apps in android. And the fact that makes it the best is the available range of customizations present in it. From icon packs to shapes to transitions to layouts, Nova covers everything in it's free version.

Other factors that contribute to nova launcher's success are:

1. It is a free launcher, that makes it more easy to attain.

2. It support most of the 3rd party icon packs.

3. The customization UI and settings are very easy to toggle.

4. You can save your favourite layout and then copy that in all of your smartphones.

I personally prefer Nova launcher as it gives me near to stock experience of android.