I'm a big fan of the koomus, and it has served me very well for the last three years. https://www.amazon.com/dp/B010NZ53EY/ref=cm_sw_r_cp_awd_-ATPwbTG2YQWQ
I user one of these: http://www.amazon.com/Koomus-Pro-Dashboard-Windshield-Smartphones/dp/B010NZ53EY Mounts in the CD Slot (I live in Texas, so I can't afford to have any part of an A/C vent blocked during the summer).