Dave I am going through the same dilemmas you. I have been seriously considering replacing my 24–70 mm with the 24–105 mm for about two years now. I had the lens in my cart at the last refurbish sale but I didn't pull the trigger at the right time. Now if I buy it I'll lose $100. I want to sell my 24–70 mm lens before I buy the 24–105 mm. I am finding it hard to part with due to the difference in cash from when I paid to what I would sell it for now. I didn't use it that much for a long time because I prefer primes but I'm forcing myself to use it more often now. I do love the lens but it is so heavy to carry around all the time. My wife refuses to use my camera because that lens so heavy. if I were to get the 24–105 mm I believe it would be better suited for my landscape photography and what I would use it for photographing my kids. I would definitely use the IS much more than I used it 2.8 aperture. I also plan on getting the 6D sometime in the near future so the loss of one stop of light really won't hurt me much comparing it to the noise level on the 7D.