1. Not optimized for the latest iPhones. (iPhone 6 and 6+ have been out for long enough to fully support.)
2. Bluetooth support is buggy in general. I have to turn off BT when I am in my car or things go wrong.
3. Seems to abuse battery. Can't confirm, but I am noticing 20 - 30 % less battery life.
4. Sometimes the red Ooma Office status bar shows for no reason.
5. Needs overall bug testing. The app has crashed on me several times in odd ways.