I've heard good things about the 305, including other posters on this forum who love it.
I'm looking for a unit that allows me to program routes into it, so I can do all my route planning at home and then the unit will tell me which way I need to turn. Ever seen anything like that? The 305 just does "bread crumbs" on the unit itself -- you have to plug it into your computer to see the route compared to roads or topos or google earth.