Which range? Googling it, Garmin make at least 4 different models all called '650'.
Most of the hits are for Oregon or Montana models - they are quite similar apart from size, but personally I'd say they are both bigger than I would want on the handlebars. The Oregon range is well-established though and generally OK - uses AAs which is good, and understands the 'industry standard' GPX files, which some other popular Garmins struggle with. So - yeh.