When Smart (Plastikbomber) it rattles a bit, but I think that more is on the ventilation grille of the smart, on which the holder could not be 100% perfect attached. But it holds very well in the smart.
The Gripper is equipped with soft foam, so that I would fix my iPhone without skin with no worries there.
I often close an audio cable to the iPhone, and for longer trips sometimes the Lightning power cables: both can be easily thanks to the optimum arrangement of the holding arms connect even if the iPhone is mounted in the holder.
All in all a great helper in everyday use.