What are the differences between Apple CarPlay and Android Auto?

Apple Carplay 

Make phone calls, access music, send and receive messages, get directions optimised for traffic conditions, and use Siri Eyes Free. Further information can be found here.

Android Auto

Make use of apps and services, including Google Search, Google Maps, and Google Play. Further information can be found here.

Simply connect your Apple or Android device to SYNC 3 using USB.