I've had a 520 for some time, I use the K Edge stem mount for mine. I've broken three of them in crashes or bashed it with my knee but the Garmin has survived.
Off topic, but bike computers came up on a group trip away to ride. Strava being Strava continues to ignore the uplift issue. We have a group training group that shows our weekly KMS and metres climbed. However it gets blown to bits by anyone shuttling and failing to stop and create a new ride every time they get on and off the shuttle? Any solution to this? It's easier with a device on the bars, I simply stop, save, then create a new ride when we get off, but it means Strava will show that I've done "three" rides that day. The rest of the group start their phones at the beginning, then don't touch them until the end of the day.