I was very sceptical if this would work or not, but was willing to try it. First thing I noticed was in order for it to get a firm grip of my phone (GS3)I had to give it a real firm squeeze in to the pad. First time I tried it i failed to press firmly enough and ended up with my mobile dropping onto the center console of my car as i set off. But i haven't had any problems since, either in horizontal or vertical position.
That being said, I am impressed with the product, it does what it says, i can only hope it can stand up to extremes of temperatures.