I finally replaced my ancient Tamron 28-75 2.8, when the price of the 24-105 got down to $725 last week. It came in a white box with lens hood, pouch and US warranty registration papers. I assume it was part of a kit.
First I did a focus test. The point of focus at F/4 was within the depth of field at both ends of the zoom range, but being a bit obsessive about focus accuracy I put in +1 AFMA at both ends to make it closer to perfect. Then I took the new lens and my 5D3 to the Portland Rose Garden for some practice.
I have to say I am very impressed with the autofocus, center sharpness and color rendering. Edge sharpness is not very important in my work, so I can't comment on that. The folks at LensRentals.com mention this lens as one of their least troublesome lenses, so hopefully it will continue to work well for a long time.
Here is a shot at F/4, 1/400, ISO 200. It's been a while since I had an image that wasn't too naughty to post here!