Personally, I prefer CoPilot. The user interface is very logical and it's got large buttons that are easy to use in a car. The male voice is very natural and clear-- it''s easy to hear and understand in the car (even though he does sound a little like Agent Smith from The Matrix ). Both products ship on a microSD card and with CoPilot you can copy the contents of the card to a larger card if you wish (which I did so I could have all my movies, music, apps and GPS software on a single card). Garmin doesn't allow this (some sort of copy protection I imagine) . Thus you might not be able to put your programs on their card either.
-------------------- Lisa Gade Editor in Chief, MobileTechReview