Is it me, or is there some reasoning-error in this sentence from the review:
"Canon offers a 16-35mm ƒ/2.8L II and a 24-70mm ƒ/2.8L II zoom lens, which -- in a way -- would provide the 24-35mm focal length range of the Sigma. However, it's split between two lenses and you'd have to carry both of them around."
Both the 16-35 and the 24-70 have the 24-35 range in them, you'd either get more wide-angle or more tele with either one. You certainly don't have to carry them both.
Anyways, I shot with the Sigma 18-35 1.8 Art for a year and a half, until I got the 6D and sold it. My main lens on the 6D is now the 24-105 L, but I sometimes missed the fast aperture of the 18-35, so I got the Sigma 35 1.4 Art. I could swap the 35 for this new 24-35, but I'm not sure I'd use it that much + I'd lose a stop of light compared to the 1.4 of the 35.