I'm looking to buy a handheld GPS unit to serve as a secondary/back-up to my main GPS on my boat. I would bring it on heavy fog days and in waters I'm not so familiar with...like on long trips. I'd also like to use this unit hiking and in car situations where GPS could be handy. I have a Lowarance unit in my boat. Any of you have any good or bad experiences with handheld GPS units? I like Garmin for this application.