What's the big difference? How about the ability to easily find interesting people, places, and events with just your iPhone and Loopt's map screen. Yawing in the middle of a droning conversation, eyes drooping at a lame party, not sure where to go in the center of sleepy-town USA? Loopt's full-scale assault one boredom just might have your back.
There's also a new version for BlackBerry, if you find that interesting.
My Canadianess prevents me from trying it (location services are typically highly region-sensitive by virtue of their content partnerships), so if you give it a whirl let me know if I'm missing out.