Okay, I know better than to ask this as pixel-peeping lenses always causes me far more trouble in the end, but now that I did I just gotta ask for your experience...
I just tested both lenses @ 70mm, pointed to a far off tree. Both @ 2.8. It appears to me both are stupid sharp, but the 70-200 is clearly a tiny tad sharper (I can see little tiny buds next to the leaves! more clearly).
As for the 24-70, I'm pretty sure I got a decent copy. I had 2 lenses at the same time (due to BH and Adorama running specials a little out of sync.) I tested both with test charts and I took the one that was very slightly sharper in the corners, though overall they were almost indistinguishable.
Lensrentals says that the 24-70 should be a little bit sharper:
Generally I trust their tests.
So, what gives? Do you guys have the same experience?
EDIT: So I did some more googling and found:
According to this posting, Roger states that "If you pick one of our 24-70s and one of our 70-200s at random, there’s almost a 40% chance the 70-200 will have the same, or better, resolution."
Sigh... I really shouldn't have pixel-peeped. Never learn my lesson. Well, I suppose that since I tested 2 copies of the 24-70 and found them nearly identical, I would say that my copy is probably somewhere around average. Maybe I just got a super good copy of the 70-200!