You certainly can't miss the TomTom Go 600. With a 6-inch capacitive display, it stands out even on large vehicle dashboards. Indeed, we'd suggest that for many cars, 6 inches is perhaps a little too large and distracting, although TomTom has you covered there with the cheaper TomTom Go 500, a 5-inch variant with otherwise identical specifications.
Still, the GO 600 is a large chunk of GPS to carry around with you. It would still be unwise to leave it prominently on a car dashboard, despite the lowering costs of replacement GPS devices. The design features a rounded plastic chassis that magnetically snaps into the screen mount and power supply.
Unlike many GPS devices, the GO 600 doesn't use mini USB but instead micro USB, which means it should be possible to charge it from your mobile phone adaptor, unless you're an iPhone user.
TomTom's interface was one that the company hadn't really refreshed ever, so the very first time you power up the GO 600 it may be a little startling to simply see a map screen and very few other buttons. TomTom has implemented a new user interface that they describe as map-centric; anything that displays on-screen is meant to be secondary to displaying the location instead.