I have a 4.5 inch screen Garmin on my L. handlebar. I can hear the voice at 50 or under, but I don't rely on voice commands except to snap me out of my riding daze. I have a "fishermans" shade ($14) that velcros to the unit and helps a lot in bright sun. I keep a small plastic bag handy for parking in the rain, I've not needed it while underway in heavy rain (Electra Glide). After saying all that, I'm a MAP guy,I love 'em. I took 1 trip without a map, GPS only, and felt lost the whole time, even though I was not. On trips I have a magnetic map holder on the tank with my route highlighted. I have a 2" stub of red grease pencil on a tiny retractable cord attached to the map pouch. I make quick marks across the route as I pass junctions. I think the real reason I like a GPS is for the ability to get back on track when I start wondering where this road goes?