I am a big proponent of not just GPS, but add-on systems rather than built-in ones. They are simply far more affordable.
Anyway, California law says these cannot be mounted on the windshield (did you know that? I didn’t for about a year of use!). So all kinds of other mounts are used. I personally use a vent mount, which goes through an A/C vent. Works great.
There is one type of mount that scares me – it’s a “bean bag dashboard mount.” This is basically a really heavy (I think I’ve seen 25-30 pounds specified..?) pedestal that sits on your dashboard onto which you then use your normal suction-cup mount for the GPS. Now, it claims to have a nice “non-skid” surface on the bottom, but it is not otherwise adhered to the dash. Which means that is could just go flying with enough G-forces. 30 pounds flying through the air in any direction is scary as heck.
Anyway, I saw one on the way to work today…