You'll miss a chunk of the scenery with the map in view . Seriously, that's only really a concern when exploring pastures new, that screens a bit OTT for most everyday journeys. I don't use a nav at all but my GF just uses her iPhone attached to the bars and an earpiece when we are going somewhere we don't already know. She has one of those old penny size BeMoto nav thingies of her Enfield but hasn't actually used it yet