Good "Always-on" with acceptable performance

The IS is very quiet and performs its function. The AF works fast and accurately.

The image quality is absolutely OK and you have to look carefully before order to make real differences to a higher value, equivalent in focal length lens can (tested commercially with the EF-S 15-85mm IS USM at a 60D). The differences are marginal and personally the charge not worth it to me.

I am thoroughly satisfied with the image quality. The distance display for manual focusing is very reliable.

Conclusion: With the ES-S 17-85mm IS USM obtained a very good, good quality processed lens, which does not need with its image quality to hide. When "Always-on" highly recommended!