So, I picked up a 24-105L to use as a primary walk-around on my XSi. I'm not super satisfied with it. I do like the focal range. I do like the image quality in good lighting, but f/4 is just not cutting it. I often find myself shooting at 105mm and more often too slow in low light. I came from a 28-135mm that I may have even liked more; good IQ, f/3.5 on the wide end, lighter/smaller. Ideally, I'd like to drop to a 24-70L and use my 100L for that length, but I get tired of swapping lenses as is.
Thoughts?

