About all it's seen so far is some mall action. It's pretty stable, it shakes a decent deal but the whole car shakes. The mount it self is solid, holds the iPad well. No worries of it popping out on a trail. If it pops you have bigger problems then holding your iPad! I could see some bulky cases having problems but anything that fits under the ears of the mount is ok. The "ball" head it mounts on works great. Passenger can easily turn it for their viewing or use.
GPS seems just fine. I haven't check what accuracy it will get yet, but when watching google maps it was right on. I know alot of people think the built in GPS isn't accurate enough but when it knows what side of the street I'm on, it's good enough for me.
This weekend heading down to Expo will be the first real miles using it. I'm looking into getting a new radio that will connect directly to the iPad and turn it into like the vehicle media center.
Over all I'm totally pleased with it so far. It's only $80 which compared to most of what we buy is dirt cheap!