X5, or whatever we are up to, for the Garmin. I have the 760 and just love it. Now that I'm a little older, I really appreciate the larger screen.
Another feature with the Garmin is the ability to add POI's (Points of Interest) to it. I am not sure if the other ones listed have this feature. POI's can be a list of low clearances, a list of Interstate rest stops, a list of campgrounds, etc.
You can build your own POI file, or go to the
POI Factory website which has thousands of POI's already made and available.