Hero 3 Black has 4k capacity, but at reduced frame rate.
What really annoys me about most of these "4K" is that the videographers either match the camera to mediocre lenses or one that is smeared with paint and include out of focus scenes in their edits. There is little point in filming in 4K if these points aren't addressed first.
I have seen a $20,000 Red camera on the field with the lens being wiped 'clean' of paint with a towel between points!
What is most impressive is the slo-mo achieved from the high frame rate,