Having both an indash unit (Kenwood KN510 - which is actually a Garmin GPS) and a portable GPS unit (Garmin nuvi 610), I would recommend the portable one. You can transfer it into any car you have or rental car for those long trips. Plus, for some reason, its a bit faster... at least with the two units I have. I also like the portable unit also because it's right there on the windshield where as the indash, I have to look down... making it a bit dangerious on those busy freeways/roads.