Just found a simple and very inexpensive mount that I'm really liking so far:
Joby Grip Tight Mount:
Amazon.com: Joby JM1-01WW GripTight Mount (Black): JOBY: Cell Phones Accessories
It's designed to attach to a tripod for photography with a smartphone. Using mounting tape, I attached it to the center console and so far so good.
A few pics are below. One of the side arms extends via a spring mechanism and then secures the phone when you release. It easily folds in and up to give your passenger more leg room and depending on where you mount it, you can keep your cup holder free. It's easy to attach power via the 12V accessory socket. So far, it's been very secure and handy when driving on city streets, easy to read, and quite easy to reach. Only drawbacks so far - not sure how well the mounting tape will last in the long run, but it seems just fine so far; I'd try to find black mounting tape so it blends in better or color exposed sides with a Sharpie; it does take up passenger leg room so where I have it mounted, it's probably not a good solution for a long drive - unless the phone goes back in the pocket.
Definitely something to consider. For about $15 (including mounting tape) it's worth a shot!
Below are some pics with my iPhone 6 in a slim clear TechArmor case: