I do not take pictures in LV but through the viewfinder. Which is set to the diopter my distance glasses, with LV I would constantly change his glasses either to recognize the motive or the display.
And here is the crux of the matter: (through the viewfinder, tested with my 70D and my 500D)
The 70D is very fast, the quasi developed 18-135 STM it. The AF is fast, but not fast enough. Knowing USM.
Especially at greater distances to the subject he meets in good light not always. Just on the 500D. On both cameras here is clearly superior to the 17-85 USM. Of course I do not have laboratory conditions, but intuitively I feel the AF by 17-85 USM faster and he sits almost always perfect.
Nevertheless:
When sitting at 18-135 STM focus is also displayed well. About CA's and vignetting I let myself here not out, other people have described. Is just a push and no fixed focal length. And affordable.
I have not purchased the 18-135 STM at Amazon but in another shop a bit cheaper than "KIT taken" in a neutral box, but with warranty and as "New" declared. Maybe it's a return, or a mounting series. I'll never know.
Conclusion:
Who works with cameras that support STM in LV or movies a good choice. Focal length is fit to travel.
Also goes to the STM cameras do not support (like my 500D) Opinion the benefits of STM.
With me that the 17-85 USM has remained the "Always top" for photos through the viewfinder, however.
While the 18-135 STM is always near but my "Manchmaldrauf".
I hope it helps you.