I do have the Canon 28-105 f3.5-4.5 and I love the lens. I took advice from the MANY people that said invest in a good lens, but really I kind of skimped on the 28-105. I spent $590 on the 70-200 f4 and spent $230 on the 28-105. I would spend the extra $80 and get the Canon but I really can't say cause I don't know that other lens.
Here's a pic I took yesterday with the 28-105. Straight from the camera, only resized and compressed.
Here's a couple pics I took today with the 28-105.