After really looking at the mounts, I chose the AMPS mount and a Monterra (no typo, not a Montana). The Monterra is a very new and kinda spendy, but I am using a lot of the Android functionality. The direct connection to power on the handlebar while keeping all the weatherproofing plugs in place was a plus. The software is still buggy . . . it is a new product and I wished they had worked harder before the release. Updates are easy, just pull within range of your wi-fi and update the GPS. To really use this device you gotta plug in to your computer and use Basecamp software. So there are several learning curves.
You can add Google Play apps, and this has really helped me make it a multifunctional device. I added apps for the GoPro camera and also for the inReach satellite communicator. So now by just switching modes on the GPS I have a monitor for my GoPro camera right on my handlebar. I can also switch from video mode to photo mode without touching the camera.
With the inReach app, I can turn tracking on and off, check for incoming messages, and send messages from inReach right from the handlebar while inReach stays in my vest pocket.