I've only used the "send to device" once and it just gives you a line to follow. Worked ok on the edge500. You get a message "off course" when you're too far away from the line, or rather when it thinks you are too far away.
I have no idea if it works for non garmin devices.
You can use the export function to save as a GPX or TCX file and then upload them to another device.
You can also probably do this directly from the Garmin Training Center software.