My TomTomOne is mounted on top of dash using the little adhesive disk that came with the unit. Sticky pad goes on the dash and the suction cup sticks right on top of it. The darn windshield is too darn far in the minivan.
Got it a bit to the right of the steering wheel so it does not obstruct my field of vision but I can see it great and reach it with my fingers without leaning. You can order these disks for about 5 bucks. My daughter has bean bag mount - personally I don't like it. Big bulky mount for unit that fits in my pocket and weighs only few ounces just does not make much sense to me. But that is just me.