The app has been improved. Though I have never had problems with it. I have heard very good things lately about the android version being much improved. I use the IOS app and it works very well. You can request the beta iPhone app from Kessil also, was easy enough. The iPhone app has a few more improvements. Again, I don't have any complaints with the app it has always done the job. They apparently had already fixed known issues because I joined the Spectral Revolution in May 2016.
Have no experience with the G4.