My speed camera solution is to use 'Speedtrap Alert'
It uses the PocketGPSWorld database that is updated weekly. STA is an Android app that works via Bluetooth via the car headunit.
When approaching a camera it mutes the car audio, issues the alert, then returns the audio.
Because it issues verbal alerts, and takes priority, you don't need to keep watching. It announces the camera type and speed and if you are going too fast it keeps telling you.
I like it.