Thanks for the insight folks.I tried 3 copies of mrk I (2 new + 1 used), none of them could gave me the results I'm looking for.
YES...mrk II has better contrast and much sharper at f2.8. This is my most use lens. Follow by 70-200 f2.8 IS II and of course 50L when there almost no light.
Many posters ended up buying this lens after they posted similar questions
Dylan, after getting the 24-70 MKII do you feel you have been using the 16-35 less and less for landscapes and wide shots? Or, the 16-35 still gets used quite often? I am asking because I have the 16-35 II, and wondering if I will end up using the 24-70 MKII more for landscapes than the 16-35 II and may end up giving up the wider focal length for better resolution.
I still using 16-35 for lanscapes. I like the effects of 16mm. Most of my landscape shots I took are @ 16mm. I'm thinking 14mm prime though, since 16-35 is not quite sharp @ f2.8.
I mainly use 24-70 for indoor family & candid photos. This lens is pretty straight forward: sharp & fast AF.