Let me preface this by indicating that my "day job" is as a geomatics professional. GPS is a huge part of my life, and I'm a bit of a junky when it comes to it. Basically, if there is a GPS device for something, I've got it.
I was annoyed that my 70D doesn't have built in GPS. I was thrilled that my 6D has built in GPS. I was really, really, annoyed when I discovered that the 6D GPS appears to keep running when the camera is shut off, and the camera's battery dies in my bag pretty quickly if I don't remember to shut it off. I don't use a grip on my 6D, as it spends a lot of time on a tripod, and I feel the grip is detrimental to ultimate stability.
Worth noting is that the GPS in my Tough TG-2 does the same frustrating thing: stays on. Which also drives me nuts.
I love GPS in a way few people do, but not at the expense of my 6D's battery. I do carry two extras for it, but the GPS could kill those pretty quick if taking a lot of shots in addition to logging.
I think I need a standalone GPS unit for the cameras.
The obvious choice would be the GP-E2. Can anyone comment on how quickly it eats through AA batteries? Does the GP-E2 have any significant annoyances?
Is it possible to connect a logger (like an actual handheld Garmin device) other than the GP-E2 to the cameras?
I want the lat/long data embedded in images when I take the image. I don't want to have to use the geotagging feature in LR.