Luke:
I have one of these Brakelighter units installed on my '37 Half Ton. I chose to only use the suction cup mounting option since I sometimes show the truck as "mostly original". I like the added safety and several of my buddies have commented they like the brightness and added visibility for my braking or turn signals. I will add one to my '46, when I get to that stage.
Before I bought it I heard some comments that the LED lights would reflect off the back window and be a distraction. I have not noticed that as a problem. It might be because of a difference in the glass shape between a truck and car?