I keep it to the right of the rearview mirror, on the passenger side and facing me.

1. It's within my arm's reach
2. It doesn't block my view
2. It's behind the darkened area of the windshield (above the AS-1 line), practically hidden from prying eyes outside
3. Allows me to hide the cable inside the narrow channel between the windshield and the headliner
4. The text-to-speech feature keeps my eyes on the road