Built in GPS is certainly doable why its m.I.a. whatever the reason its not an engineering problem. It could be as simple as Canon & Nikon waiting for the other to show their hand. Now Nikon should release something, possibly built in & then there will be a good chance GPS will become the standard fair.
Its big & expensive but I'm glad Canon has released it because the alternatives are not great.
If I remember correctly you can leave it in your pocket (just remember to turn it on) and sync with your p.c. later.
Duh... I just realized they must have developed the new radio flash tech, Wi-Fi & GPS in conjunction with each other. Hardware wise its much the same so.....
Its all good.