I really wish Canon would ad 5mm to the top end of the 24-70.
It just doesn't have enough reach on a full frame body.
I use the Tamron 28-75 and wish they would make a 24-75 as well.
I do find it amusing when Tamron 28-75 users say the Canon 24-70 just doesn't have that extra 5mm on the long end that they need.
FYI - The Canon 24-70 L has MORE REACH at the 70mm end than the Tamron 28-75 does at 75mm. I own both and have tested this. The Tamron is a pretty horrible lens, feels like a toy from a christmas cracker, focus ring is a joke, soft @2.8 and that 75mm is misleading.
Having said that, the 24-70 isn't brilliant. Wish I could afford to update it when the new version appears.