Sigma 24-105mm f4: 88.6mm x 109.4mm, 885g, 82mm filter
Canon 24-105mm f4: 83.5mm x 107mm, 670g, 77mm filter
Nikon 24-120mm f4: 84mm x 103mm, 670g, 77mm filter
Tamron 24-70 @ f4: 88.2mm x 108.5mm, 825g, 82mm filter -> and we need some MTF's. So simple. And yepp, it's stabilized as well.
If you don't realize it lacks between 50% and 70% focal length (35 or 50mm) and if you think a wide open not useful lens is okay to compare, just because it has sort of similar weight and filter size - well, why not. :unsure:
But don't forget half a dozen other 24-70/24-85, oh, and why not take a 28-300 into comparison?
If you compare lenses with such a difference in focal length it's just not what I call comparison, and I put the 28-300 only in to exaggerate towards the other direction. For a lot of people 70mm is just not enough - and for those who are happy with it there are already more options than only that Tamron you find so interesting.
So, why exclude those from a comparison? And by the way: Hey, why don't YOU do the comparison and tell us what you found? I mean, it's always easier to tell others what they should work on instead of doing it myself.