I have had rental cars with them and I want one too! My brother had a portable one that he used to move from the west bank of New Orleans to Oregan and he said it was WONDERFUL! He punched in from day to day, where they were and where they planned to stop for the night and it worked like a charm.. As much as I travel for work, I would love to have a portable one but half the places we have to go to catch the boat are not on ANY map or even have a address...