I'm very partial to my 24-105 f4L. It's my 'main lens' for everything I do. Yes, there's times when I want to go wider, so that's my 16-35 f2.8. And when I want longer, it's 80-200 f2.8. But in general, the 24-105 is used for perhaps 80% or more of my photography. There are those who will pooh-pooh the f4, but after having had a 24-70 f2.8L 'the brick', the lighter weight and IS of the 24-105 outweigh the slight sharpness improvement and 1 stop of light the 24-70 offers.
I used both on my 60D when I owned it and liked the results. In my mind, the crop sensor gets its light from the center area of the projected image from the lens. That's the sharpest, least CA, least difraction, eg, 'best' area of the image. Today have have only the 24-105 (plus 3 other Ls) and a 5D3, and it's still my favorite lens.