GeoTag 4+

Good
* One or more GPX files in the same directory as the phots are read automatically.
* Manually tagging using the map is easy.
* Supports RAW files.
* Nice layout of list, image, and map.

Bad
* Cannot adjust the location accuracy.
* Cannot adjust for a time offset.

Bug?
* Locations got randomly assigned. Out of 50 pictures on a hike of a few miles, the last 40 got the exact same location. Seems to be an issue with multiple GPX files being saved in memory since a new set of photos and GPX got assigned to a previous track -- from a different location and date!
Clearing the image list didn't always seem to resolve it, but closing and reopening the program for each new set seems to apply only the locations that positively match.

Time offset may be a dealbreaker for some, but for free, this is a good app.

With Aperture going away, I decided to switch to Capture One 12. One of the advantages of C1 is that it imports native Aperture libraries. One thing it doesn't do is easily let me geotag photos. Aperture connected directly into Apple Maps and made it easy to add that information. C1 does not, so for those photos that don't have location data embedded, I needed a simple app to do that. This one fits the bill perfectly. Unfortunately it adds a few steps since I need to geotag the photos before I import them into C1, but it does the job. I do wish there was a way to enter, say, a city/state/country or whatever into a search box. That would make it easier to locate an area as opposed to scrolling around the map.

This free app makes geotagging photos very easy. The interface is intuitive and easy to use. If an entry mistake is made, it is easy to correct. I use it in conjunction with a couple of Nikon cameras and an iphone running the Gaia GPS app (for recording the track). Making sure the camera time is properly sync helps! However, Geotag does allow placing photos at the approximate location in the absence of proper time sync or a track. It works with multiple tracks loaded.