I also use a Garmin Zumo 350ML. I like *most* of the features in terms of mapping, setting waypoints, tracks, routes, etc. The importance of setting waypoints, is YOU choose your route. If you leave it up to the GPS, you have a choice of fastest route to destination, or shortest route... period. Not necessarily the *best* route for a motorcycling (although the new Zumo 390 will guide you to the "twistiest" route).
For any kind of flexibility and comprehensive featues in mapping you're looking at >$250 USD. Used is an option, but factor in the cost of updating the internal maps when/if you buy used.
2017 Pearl White 650[/B]
AdventureTech lowering links and GPS mount
AdventureTech +2" SS braided brake line
GPI spools, SW Motech risers
Givi XS307 Tanklock bag and Givi 46L top case
Suzuki hard case saddlebags