I had a mount, but it broke. Not when riding, but when packing the bike up. But I didn't use it much and haven't decided if I should replace it.
I haven't bothered with paper maps the last several trips. But I don't use the phone for navigating. Or, at least, I don't use turn-by-turn directions. I'll generally have my route stored in my phone (or sometimes my tablet) along with downloaded maps of my route. I just pull it out and check it occasionally. The battery lasts longer that way, and I don't have to worry that I'm going to pull the phone out and find that I'm in a dead zone, and the maps won't load.
I do rely on Google directions a lot, but I tend to take screenshots if I'm worried that I will need to reference it off line.