I can't comment on anything but the Push notification service, but we've been super impressed; it's so much easier having our backend just call the Parse REST A

I can't comment on anything but the Push notification service, but we've been super impressed; it's so much easier having our backend just call the Parse REST API and have our iOS clients register PFInstallation objects and assign themselves to channels than it was to setup enduring TLS sessions to APNS on App Engine.