But wait, as the showman says, there's more! The 2.0 update released today also enables ticker text in the notification bar with the $2 pro version upgrade. Ticker text is what you see when a new notification arrives and the first few lines of a message appears in the notification bar. If you want access to that function for all notifications in Lollipop, here's the ProKey - it's a separate app, so you can try it out and return it if you don't like the result.
The pro version of HeadsOff allows you to enable and disable heads up notifications on an app-by-app basis, so if any one app is being particularly annoying you can disable it alone. A checkmark in the app menu means that the heads up notifications are disabled, and there's an all or none function as well.