It's definitely a streamlining benefit to get the GPS coords embedded right into the photo at the time of capture, but as mentioned, the firmware on the Nikon cameras, the last I heard, didn't use as much precision as you could get from the GPS logs.

That solution is priced reasonably if you consider it's a hobbyist effort. Crazy expensive if they've sent it off to China to make 5k at a time.

Even with GPS coords within the photos, you're still going to have to do a parsing step. Well, that actually depends on whether you're satisfied with only the coords or not. I'd be running it through software to pick up the coords and then reverse geocode them to find the location names (country, region, city, street), then embed that data as well.

Units that sit on the hot-shoe are not an option, IMO. Too many negatives, including sucking too much battery power (some of them), flimsy cord (all of them) and the biggest issue is they block the pop-up flash. Obviously they also take up the hot shoe, so forget about mounting a remote trigger. Blocking the pop-up flash is a big issue for me because I'm using it as a remote to fire external strobes more and more.

An additional benefit to an external unit is being able to use it with any other camera. That BT receiver thing you linked seems to be the best of all worlds really. I'm just worried about that lack of precision I've read about.