I have the Samsung Car mount, and I am very disappointed.
It is a pain to insert the phone in the very tight clips, then you have to slide the usb connector into the phone, an exercise that takes two hands.
Further it does not accomodate even the very thin Samsung flip cover.
It forces the phone into car mode, which requires voice input - which does not work. - at least with my voice. I cannot call 'Nora' it will only find Laura - and I don't have a strong accent. It has no means of understanding what 'Home' means.
And now, after a month, it appears that contacts inside the car unit are flakey - the phone goes crazy when I plug it in.
So great phone, but they screwed up royally on the car mount.