GPS in a dSLR is critically important to me. I photograph archaeological sites and location is really important. In fact, I bought a 6D just because of the built-in GPS.
I am not wild, however, about the accuracy. I am usually outdoors with a clear view of the sky, but still see that points wander about when they should be at a single point.
I wonder if the GP-E2 is more accurate and REPEATABLE than the built-in 6D GPS?
Rick
