Garmin GPS units are fairly popular, though more expensive than the item you linked to. The bike-specific Edge models have larger displays for maps. Smaller models like the 910XT are targeted at triathletes. They can be worn on the wrist (not recommended on a bike, because it’s difficult to look at the display) or on a quick release mount on the handlebar.
Other companies sell similar products: Timex, SUUNTO (not sure if they have GPS or not).
Is anyone willing to send me a sample file of one of their rides? I’ve tested one GPX file already, but it won’t work because it didn’t have a time stamp, and the idea is to overlay multiple trips, so I need to know the times.
Now I have to figure out: what is the best way to get a group of 100 or more people to send in their GPS data? Maybe ask everyone to get MapMyRide for their smartphones, then export the GPX file, then email it in.