An alternative. I have a Garmin sat nav and indeed the Fezza had one built in but what I used on both bike and car was my phone running a free app called Here. But because I find peering at a screen a distraction I use blue tooth and get the instructions in my ear..
Its brilliant, and far better / safer than having a mini TV set fastened to your windscreen. Had a few dodgy moments fiddling with a screen based sat nav.
Here One of those rare occasions when the best option costs far less than the second best option.