[no_protocol]

If you can only afford one lens, it's a fine all-around piece. It just isn't as good as some other choices. Many have complained that it is too soft. I was explaining why this combo is at the top of the list and commenting that it's popular, but not "the best" combo.

[hrrsn]

It's definitely not a bad lens, but I did find it really soft. I replaced it with the EF 24-70mm f/4L which is leagues sharper.

[ekianjo]

You said that it is just not very good. Go ahead and try to find a 24 105 lens that can outperform it at the same price range.