As an owner of a Nissan Quest with a built-in GPS, I have plenty of frustrations with static GPS devices. The map on our GPS was outdated by the time we bought it--it actually routed us to a dead end one time, a place where an earthquake had destroyed the road and none had been built to replace it. It often shows us driving on blank map because it has no record of the road we're on, or gives false directions. On top of that, Nissan wants us to pay them for an update DVD (that will also be outdated by the time we get it). We have just given up and gone back to paper maps because they're more reliable and easier to use.
What's different about Dash is it's actually getting smarter as time progresses. Because it connects to the internet for information, not only does it have up-to-date roads, it's also got real-time traffic updates with the ability to route around traffic jams (how handy!) and a plethora of other information you might want when you're out and about. Things like "what live music events are happening in town tonight and where are they?", "how much do the houses in this neighborhood cost, and where are the open houses today?" are now doable from your car with this handy Dash device. It even has built-in theft protection. When I saw it, I immediately wanted one, as did just about everyone else in the room. Unfortunately, by the time I reached the guys to volunteer for the roadtest, they already had enough volunteers. Sigh. I would have loved to evaluate the usability of the device. I guess I'll just have to wait ...
Glenn on AnyGeo posted a couple videos that I've taken the liberty of repeating here. Be careful watching these: you may find yourself wishing you could get one right now, like me!
and a video clip from the Web 2.0 Summit