What really makes MotionX GPS so great is the developer's extensive attention to detail--the units of measurement and navigation are fully configurable along with display format--as well as the app's complete functionality. While MotionX GPS may take a bite out of your battery, the developer even provides the option of turning off accelometrics-assisted GPS to save power.

As if all these great features didn't impress you enough already, MotionX responded to the cries of the community by including iPod functionality within the app, so you can still listen to your favorite tunes while MotionX GPS continues to track your movements. A recent updated also added magnetic compass integration with the iPhone 3GS.

The only features I found missing were the ability to automatically generate waypoints over a period of time and a more detailed display of climb and descent over time. The latter feature would allow you to use the information more accurately for training purposes.

In addition to the , MotionX also offers a , which limits the amount of tracks and waypoints you can have and removes customizable features such as display formatting and waypoint visibility. Regardless of which version you use, anyone who downloads the MotionX GPS app should check out the extensive documentation provided in the app itself and on the .