I used to be an advocate for Urban Airship when it comes to sending push notifications.
They are the very first to provide a simplified solution to iOS push notification, and they even offer 1 million push messages per month, for free (which competitors all follow).
But thereafter, it will cost 0.1 cent per push message.
Let's compare the pricing with Parse.
|API Provider||Per message||Per 1 million message|
|Urban Airship||0.1 cent ($0.001)||$1,000|
|Parse||0.007 cent ($0.00007)||$70|
So, Urban Airship costs 14 times (1000/70) of Parse!
Parse is the obvious choice to me.
I would have choose Parse if it was available in 2009. But it's not late to switch.
What's more, Parse offer not just push messaging. It includes a very awesome mobile cloud backend, signup module with Facebook/Twitter, lost password, push from clients over channels, cloud code, very good documentation, SDKs, etc...
I now advocate for Parse.