Just used PE on a trip down to Costa Rica and it worked quite well. I really like this app, being a map junkie.
Anyways, a couple of times I missed a turn or two because we weren’t actively paying attention to the route on the screen — it would be extremely helpful if the phone will trigger some audible cue (a ding, or some kind of sound) when you are at a point that you were supposed to turn to. If the phone is on “silence” mode then it could trigger a vibration instead. If the phone is in the background, pushing a local notification would be extremely helpful as well.
Also, another helpful cue would be to possibly change the color of the transparent ribbon indicating your next turn, so that it changes colors as you are approaching the point — ie blue when you are a mile away, yellow when you are half a mile, green when you are at the turn point (plus audible cue) and red when you passed it and you are now off route). The distance/warning ratio would depend on the speed.
I call this Proximity Alert. Months ago, I suggested to have a Waypoint Navigation system (similar to garmin handhelds) wherein we can create a series of Waypoints, when we get near a waypoint, it would alarm alerting the user.
I believe the devs are ‘working on it’.
It would however be best also to have a “Turn By Turn” direction as well and having said that, a true OFFLINE routing. I used PocketEarth very recently to navigate through Super Typhoon Haiyan’s disaster areas in the Philippines doing relief work. There is NO mobile phone service nor internet – no way can anyone get ONLINE routing with that. But my brother’s Android phone got offline routing.