I've been using my Garmin Montana 650 for navigation and rowing performance.\r\n\r\nIssues:\r\n1. Proximity alarm boundary disappears from chart display when the referenced waypoint scrolls off screen.\r\n2. Maximum Speed is only valid for Current Track. If you save and clear the track, the Maximum Speed information is lost and irretrievable.\r\n3. Plugging in the SD memory card with LakeVu HD charts only displays on the Montana 650 screen. LakeVu HD data will not download or display on the BaseCamp software which is used to display trip information on a PC.\r\n\r\nI was expecting more functionality for my 0. \r\n\r\nOther than those 3 issues, I'm happy with my Garmin Montana 650.