This mount stays where you put it
I haven't used a window mount for my phone before. Mainly because the ones for my GPS units over the years have fallen down - a lot. But when the iBolt miniPro Dash Kit came up for review, I knew I should finally get over my fear of falling and try it. I've got a coverage plan for my phone for a reason, after all. That said, my fears seem to be unfounded. The iBolt miniPro has stayed bolted to the windshield without fail.
Inside the compact box, there is not a lot that comes with the iBolt miniPro. You have the device grip, the suction-cup mount, a dashboard mount, a much smaller adhesive-backed mount, and two alcohol pads to clean your mounting location, which you should most assuredly use before you try to mount the iBolt miniPro. The box also has a device sizing guide on the side.
Mount it and leave it. That's why there's two.
The key to keeping this mount holding strong is to not fiddle with it a lot, as there is adhesive on the suction mount that will wear off if you continuously remove and re-position it. Find a place for it and keep it there. The spring-loaded grip works well, gripping the device tightly but releasing it with little fuss when you're ready to get out. As with any spring-loaded system, the bigger the phone, the more hassle it will give you. I wouldn't use a phone much bigger than the 2014 Moto X with this mount. The device grip will swivel with only slight resistance and rotate a full 360 degrees, and I haven't had it slip any between my rotations and tilting.
As far as using the smaller adhesive mount, you'll have a much smaller range of motion with it while it's mounted to your windshield (or any other flat surface you decide to slap it on), but switching the device grip between the suction mount and the adhesive mount is quick (less than ten seconds) so if you switch between two vehicles frequently, you can have one mount in each car and switch between them by taking the device grip with you.
The iBolt miniPro will see you and your moderately-sized phone through your daily drive or rough roads (a friend is asking about mine for a storm-chasing vehicle), and you can buy one from Android Central here.