I just got the Kenu Airframe. For my wife's 2009 Mazda 5, not so good because even though the case held her iPhone, the vents on her car humped up to the steering wheel and couldn't see it.
But for my 2006 Mazda 3, GREAT. Maybe even better than the dock because I can easily reach it. I took the audio cable coming out of my GROM and hooked it to the phone, and hooked the charger up too. I prefer the dock where you don't have to plug and unplug it, but it worked great.
I have GROM for iPod. Now I need to decide if I want one for Android and give the GROM for iPod to my wife who has an iPhone.