I've used UrbanAirship on a few different projects over the last couple years.
I'm looking for something else now. Why? Because UA doesn't provide any feedback metrics. I don't know what you are using your push notes for...but I have found that I want to know which push notes users take action on and which ones they ignore and there is just no facility in UA to track that, where I am seeing this feature available in many other offerings. Still looking...but I'm done with UA I think.