I feel the ones which fixes to windshield is more annoying while driving, thats my personal thing, but think
it blocks a part of vision & distracts me badly.
I prefer the Non SKID mat type thing just below the windshield and Cell Place on on, one can make some foam based arrangement
so your mobile gets seated properly and it also Helps in GPS as clear view to sky is possible.
you don't need to see GPS screen all the time so Its pretty safe to have it just on Dash facing towards you and you become
used to having a glimpse of it when you are on crossroads.