I'm considering getting one or the other of these lenses (to use mainly on a 40D, replacing a Canon 28-135 IS). Michael Reichmann compared the two a couple years ago and seemed to conclude that, on balance, the 24-105 had slightly better image quality. Most other professional reviews I've seen come to the opposite conclusion. User reviews on retail sites, Fred Miranda, etc are all over the map. (I realize user reviews are often just that - more about the user than the product, but even selecting the more thoughtful reviews it seems there's a wide range of experiences.) So I'm looking for opinions here, especially from people who have used both. I'm concerned with image quality from the standpoint of acutence, resolution and color - not so concerned about distortion. Focal length range, size, weight, etc will affect my decision only if image quality seems like a toss-up. Or if anyone thinks I'd be wasting my money and should keep my 28-135 I'd like to hear those opinions too.
Thanks