It is easy to use, accurate, and surprisingly doesnt use a ton of battery on continuous mode. I attached a cheap external battery pack that holds 2 AA batteries and left it on continuous mode for over 7 hours and my phones battery was still at 100%. Next Im going to try it without the external pack and see how it performs then.
One thing blatantly missing (unless I just didnt find it) is the ability to see the distance traveled. I think this would be a really useful function, and shouldnt be that hard to add. Obviously it wouldnt help much with the photos themselves, but after a long day of cross country skiing, for example, it would be nice to be able to quickly see how far we had traveled.
As for the desktop software, I couldnt get it to work. I tried the offline method and the online/uploading method and in both cases it just said that it couldnt find any location information. Im not sure why it wasnt working, but it wasnt. I am using Aperture 3, however, and there a feature in it that lets you embed the gps data into the photos directly, so I didnt really need the extra desktop software. Just sent the data by email and used Aperture to do the rest. Then, after tweaking some settings in Aperture and in Flickr, was able to get Flickr to recognize the gps data on upload as well.
Overall a great, simple app that gets the job done.