I know it isn't something that you see on this forum very often, but I just got back from a quick 3 day backpacking trip to the Pecos Wilderness here in New Mexico and I am very happy with how the watch functioned while navigating, following a preset course from base camp, and getting us back to camp in a horrible rain/hail storm with limited visibility. The wrist HRM could have been better at times but for any activity where I'm serious about recording HRM I'll use my HRM-Run.
Activities are here
https://connect.garmin.com/modern/activity/1996950060
https://connect.garmin.com/modern/activity/1996952235
https://connect.garmin.com/modern/activity/1996957797
https://connect.garmin.com/modern/activity/1996961100
Battery life was great, GPS was solid, and the ability to see my previous path and the map on the way back from our summit attempt on Truchas peak was key to getting us back to camp safely in conditions with extremely limited visibility. Overall I'm really happy with how this watch has performed and the map features, when used in the wild, were very useful.