Canon 28-135mm VS. Sigma 18-250mm

My Canon EOS 7D with 28-135mm zoom lens It works as a great pair. But I travel quite often, the wide angel part I missed was inconvenience to me. So I bought a Sigma 18-250mm f/3.5-6.3 DC OS HSM IF Lens for Canon and put these two lenses side by side to make a comparison.
As you can see, these two lenses are similar in length, though Canons 28-135mm is much more handsome. I also used both lenses took test shots on a tripod, the results are almost identical, I couldn’t tell which one is better or worse.

To the end, I sold this 28-135mm online for a good price, and kept Sigma. So far, I am very satisfied with it’s performance.