Hi,
I have both lenses, 24-105 f4 (v 1 & II) & the 24-70 f4, and use them all a lot. I am surprised that no one mentioned the wonderful MACRO feature of the 24-70 f4. That is one feature that helps tip it for me. Also, I am trying to save my aching neck these days, and the compact size of that lens helps a lot. Having a choice is best IMO. These are both really useful glass IMO.
So long for now, Tom