My wife and I both shoot. We have a 1D3, two 7D, and a 40D, and just added a 5D3 to her (our?) bag two weeks ago. We have the 24-70 v1 and the 24-105. I don't mind the weight, and I reach for the 24-70 EVERY SINGLE TIME. I could care less about the 24-105. The 24-70 has magic air inside or something...I love the results I get. I find the 24-105 to be good but never amazing. I frequently open up my bag (which usually has 10-22, 24-70, and 70-200/2.8IS I, along with 1D3, 7D, and two flashes), put the 24-70 on the 1D3, leave the flashes in the bag unless I'm fighting sunlight, zip up the bag, and save the rest for later if I need it. Keep in mind that the 24-105 was my starter lens, and the 24-70 didn't land in my bag for about three years though I'd rented it a time or two.