I tried to use multiple GPS devices and the up I saw was the low battery usage!
This app allows you not only use one device for everything but if you are concerned about hurting it you can get an old iPhone for $50 and download all off read maps over wifi hence no service charge for expensive and slow map on demand downloads.
As to the features? Top notch we used GPX tracks that we loaded and it worked great by showing if we where on track and which direction we were going.
The zoom works great and allows immediate orientation while stopped as well as great update as where to turn when zoomed in.
Overall this is a great GPS with all topo maps you need, only get an iPhone with at least 16GB and you are off-road ready!
Best GPS I have found!
Start using it by just using zoom and bottom middle button and get used to other features on the go like distance measure and many many more! Love the App!
Starbertl about MotionX GPS, v24.1