I bought this lens, and after extensively comparing it to my Canon 24-70 f2.8, I sold the Canon. This is an outstanding lens.
Same here, I love it too.
If you are comparing the Sigma to the Canon 24-70 f2.8 Mk I
it should be noted that I sold my 24-70 f2.8 too, but after getting the 24-105L, because the 24-105L had much better resolution and I was more pleased with the color saturation it provided. The Canon 24-70 f2.8 Mk I
just wasn't that great.
I think a more direct comparison between the 24-105's probably leaves little to be desired over the Canon especially if you like to process in DPP (like me) and thus have the OEM Canon lens profiles and camera settings available in post. Other than this I *really* dislike lenses with a duo-cam zoom mechanism such as this Sigma has for mechanical reasons and the appearance which associates it with cheap, wobbly builds of the past.