I read a review (MCN?) on an Iphone bike mount. The tester commented that although the mount held the phone fine, the vibration was enough to make the phone act flaky and that it was very possible that an Iphone couldn't withstand regular use on a bike.
The latest Aerostich catalog has leather glves with conductive thread in the fingers just for this very reason. Very hard to find on the web, but I found it. http://www.aerostich.com/aerostich-elkskin-roper-gloves-21.html
Certainly if your GPS can actually talk to you, that has got to be safer than looking down at it or looking down at a route sheet. It is all about inattentiveness or possibly more accurately about distraction.
I've done some digging and there doesn't seem to be a way to transfer GPS files to an Android phone. I like my Garmin better anyway. Maybe iPhones do a better job.