I plan routes on Strava and sync them to Garmin. This worked faultlessly on my Forerunner 945 and continue to work as I still use the mapping function on the watch as well as my Edge 840. And I am glad I do as I have now had a route fail on me twice on my new Edge 840. Both times the route looked fine when I synchronised. The route looked fine as I was going along but part way through two rides the Edge appears to not like an upcoming part of the route and then stops. The route is now shortened until it gets to the part where it has stopped. I tried recalculating but this did not work because it just recalculated to the end of the now much shorter route. The cause appears to be that the route included a section of route that the map did not "like". Either it was a footpath or not a recognised road. Once it does not like that section it stops navigating and cuts the route short. I carried on for a few miles (using my trusty 945) and it never found the route again. There is a work around. If you delete the route, load up Garmin Connect app on phone and re-sync the course it works. This proves the route is ok and having now travelled past the troublesome part of the route you can continue as normal. So Garmin, please look into this bug. I have no idea why the navigation and mapping is so different on the Forerunner and the Edge, at least one of them works ok!