Which zoom to buy with 5DmarkIII?

AF not as good with the Tamron as the 24-105.

I have owned every one of these lenses EXCEPT the new 24-70 F4

the 24-70 2.8 I was soft wide open.

the 24-70 2.8II is near prime sharp. At F4-8 it is PRIME sharp.

The 24-105 is sharp, even at F4 and VERY sharp at F8, but has a lens distortions.

If you have the money, the 24-70 2.8II, otherwise,the 24-105 F4 is the walk around lens.

The Tamron sharp but the AF on my 5DIII was no where near my 24-70 2.8II