Is there any reason to use Google GCM vs Apple messaging for push notifications?

Question

Google has this Google Cloud Messaging info for integration with iOS

What is the difference between using Google Cloud Messaging or iOS for the same purpose?

Is

Answer 1

In addition to the other answer, GCM supports upstream sending (sending messages from the client to the server), which APNS does not.

Answer 2

Google Cloud Messaging is originally a platform to send notification for Android. They added an iOS SDK, but using their SDK on iOS means that you are using both GCM and Apple Push notification service:

Push for iOS device => Google Cloud Messaging => Apple APNS => Device

If you are only developing an iOS app, it is best to use APNS directly. If you already have all your infrastructure set up for GCM, then you may save you a bit of code by supporting only GCM to address both iOS and Android.

However there is no specific technical benefit doing so.