Here's a bit of a comparison on a data overlay.
I'm more and more impressed by the Laptimer App i use.

Its at the point now where you an import video back into the iPod or phone after the event, sync up the finish line and then it will overlay all of the data into a finished video.
You can choose a lap, a number of laps, or even a whole race if you wish.

This was one of my funnest laps of the day as well.....