Good topic. Only one bit of slightly off topic info I'll add right now. This info from a friend who retired from the telephone company. If you have a means to continuously charge phone in/on vehicle, this is not an issue, but if you are relying on the phone's battery, here's what he told me a few years back.
When riding in remote areas (where there is no cell tower coverage or it's intermittent), turn your phone OFF. He told me that when a cell phone loses signal from a tower, it starts searching for another cell tower signal, and it keeps doing that until it finds one. Worse, this is the thing that most saps battery power. So, e.g., in riding from Auburn to Reno ~100 mi.), even though there are several cell towers along that way, your phone is searching and changing towers so frequently and so long that by the time you reach the other end of that ride where the towers are providing constant connection, your cell phone battery is very low. Turning it off avoids this.
Unless you have an on bike phone connection like Jeff (bikeffects) with his slick Starcom and Zumo caller ID setup, you can't answer the phone or call from it while on the bike anyway. So turn it off until you stop. Then you can call your voicemail and see what you missed, even though your phone won't display missed calls that were made when it was off.
I always carry mine in the inside breast pocket of my jacket, just in case I do an OM and land somewhere away from my bike. Hopefully, I can get the phone out, turn it on and get reception. I make my pillion do the same with her phone.