The only problem that Ive had with this app, and I use it quite a bit when trying to get in touch with my friends before and after group playing, is that the messages pop up MUCH faster on the PS4 itself and it can take a few minutes before they pop up here. There is a time lag that can be frustrating at times. But, many of my friends that I play in groups with live across the world from me, so I think that is partially why it takes longer on my phone. The other thing thats not consistent is the alert system. Many times I dont hear the notification alert I have setup. I presume that its because it never wakes my phone up like regular messages.
The really nice thing about having this messaging system is that you dont need to purchase a keyboard for your PS4 messaging, plus, you can remain logged into your ps4 on both devices at the same time, which is very helpful.
I dont know anyone whose having so much trouble as the ppl who said it wont send, but perhaps the developer has corrected those problems by now. App works great for me. Hope the same for everyone!
QBKohl about PlayStation Messages