Like many, I use my iphone to log strava (now with added heart rate monitor, which rules out airplane mode is it uses bluetooth) and a good ole fashioned paper map.
I usually plan well before a ride in unknown parts, and am pretty decent but am not immune to going a little off track. (last time it was because I saw an inviting trail and thought be rude not to go down there..)
i tuck the phone away in a waterproof case in my bag when i start to ride, and only ‘sync’ once back in the car and on the power. (a habit from my old phone as it would die otherwise)
I don’t want to use a live mapping app on my phone for fear of battery loss or an emergency call. (if there’s even a signal..) but i can see pre-downloaded maps might be a win, but still, i don’t want my phone exposed to crashes, muck etc.
i’d be very happy with a cheap, lightweight handheld gps that shows pre-downloaded maps, my location and no other things required apart from maybe a compass. optional uploading a gpx/waypoint could be useful, but thats all. satmap 10 looks kinda nice.. i’d stick with it for those rides in unfamiliar territory.