If your device lack of ambient display, or you dont like it/use it now you can!!
Choose the aplications you want to get notified when your screen is OFF and see them in a nice way.
Battery drain is 0.
You can choose quiet time, to not turn on screen on notifications from selected Aplications during this time.
Every Notification watch and text color is generated from Aplication icon color, so it is very easy to notice!!!
HOW IT WORKS?
1º)ENABLE THE SERVICE
2º)CHOOSE THE DESIRED APLICATIONS
3º)CHOOSE A QUIET TIME IF YOU WANT
READY

From now on every time your screen is OFF and you receive a notification from any of the selected Aplications, the screen WILL TURN ON for 10/12 secs to show you the notification in a nice way!!!
If you want to turn OFF screen before simple tap on the screen, and if you want to go the lockscreen simple tap twice!!