I've been reading reviews of the Dash Express, which is just being dropped into general availability, though it appears that Amazon won't be shipping it until 27 March, 2008.
There doesn't seem to be a lot of data available yet comparing the Dash Express with currently available devices. Since I need to do this anyway, I'll come up with something for the Dash Express, my now back level Garmin nuvi 650, and a current traffic enabled Garmin nuvi.
Ok, first possibly fatal problem is that it's not clear how the Dash Express can be transferred between cars, which is a problem since I most often need GPS when in a rental car. And, since I travel a lot in rental cars in California, I can't affix the mount to the window, by law. Dash support says they're aware of the issue and it's not a straightforward fix, since the unit is bulky and heavy.
(to be continued)