I just tested the plugin both on iOS and Android and everything works fine. Not sure why some of you have issues but I think you might have set up something wrong.
Please remember that you need to update the config.xml file and specify the version of the plugins as below:
<plugin name="cocoon-plugin-ads-ios-admob" spec="^1.0.0"/>
<plugin name="cocoon-plugin-ads-android-admob" spec="^1.0.0"/>
If you use iOS with Cocoon 3.0 beta, then the version should be
<plugin name="cocoon-plugin-ads-ios-admob" spec="*"/>
Apart of that there is nothing fancy to set up. It all works both on Android and iOS with the current plugin's verison.