Hello John, your post is a little confusing due to your writing
"I am not a GPS user"
"Both do what I want"
and stating that you find it dangerous to have a gps mounted.
Still, moving right along!
Yes- I use an unmounted system- in fact two devices -both handhelds but can also be mounted.
Both of which I use on and off mounts.
Some mounts have speakers built into them so you can also hear navigation instructions. ( The 62S does not have voice but the Montana does)
Mounted in/on vehicle for navigation makes it easier to gleam information at a glance and leaves your hands free to control your Bicycle/scooter/motorbike/4X4 or camel !! (although finding mounting points on one of them isn't the easiest thing in the world to do!
Both can be fed by vehicle 12 volts saving their internal batteries.
The Montana has a Li-Ion battery but can also run on3 AA batteries ( the 62S uses only 2AA's)
Garmin make excellent maps and you can also obtain (for free) OSM maps.
Have you thought about attending a HU meeting?
You will be able to see many different types of gps units and question owners there and/or attend navigation presentations.