Im not one to write reviews, but I really like this app. Its really easy to use, but what I like best is how you can use the track to geotag the photos. The app provides many different ways for you to accomplish this task, so you just need to pick the one that works best for your workflow. There are two that I use: Ill use the iPhone to record my hike (I like to photograph during my hikes), but Ill actually shoot with a digital camera, not the iPhone. If Im just shooting JPGs, Ill upload them into iPhoto when I get home so that they go to my photo stream. Then I just open up this app on my iPad and it loads my photo stream and automatically geotags the photos I just took. Couldnt be easier. The other way I use it is when Im shooting raw (which is most of the time). You start out the same way, but when youre all done, you instruct GeoTagr to email you the GPX file. Once you have that, you can import the photos and the GPX file into Aperture (or Lightroom) and sync the GPX data into the raw metadata and voila, youre photos are geotagged.
Lastly, the support is great. Ive only had one issue (and it was my fault), but the developer replied within minutes (on a Sunday no less). Id buy this app again in a heartbeat.