Radar is line-of-sight. So is laser. The higher it's mounted, the better. I've seen some articles saying center of the windshield, but it'll get too hot there and also block some of the view.
I see so many detectors placed so they're pointed at the sky or so they're "looking" through the wipers. My RX-65 goes off when the bear is still several hills away. It's placed just below the tint eyebrow, so it has a clear view and is still shaded by the eyebrow. I use the same location in my Ram.
Two of my recent tickets were laser-generated. The only way a laser detector will save you is if there is some bounce off the true victim's car and your detector sees it. Otherwise, you're toast.